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3704 Views 16 Replies 9 Participants Last post by  tungtide

UPDATE APR 2020: (almost 4 years later)
PART 1: The Water Pump

LOTS OF PHOTOS! ... (slow day at the
(Note: click any photo to zoom)

Here's my original 92 "custom over-sized radiator upgrade" installation (2016):

Well, despite having successfully installed a "massive over-sided radiator" in my 92 V8 van almost 4 years ago, my van has recently starting running a little hot again (on highway trips). Temperatures on hot days have been climbing to over 200+ and holding .. which should NOT be happening with a radiator this size. A few years back when I first did this upgrade, it used to run SO cool in the summer on the highway (see link above)

I haven't been running a thermostat (the electric fan would stay off until higher temps kicked it on)... so I finally installed one. I had a thermostat in originally, but had pulled it some time back (doing several system flushes), and never got around to putting it back in. I learned I would also need it in the cooler temps, as it would run cold when outdoor temps dropped below 80.

So this was to be an easy first attempt fix. I've seen it suggested the thermostat "may be" important to flow control... so I wanted to rule this out first to be sure this wasn't actually causing my issue.

A few months ago, I had flushed the coolant and replaced with new (while I was doing the thermostat). In this photo, I'm actually using a shop vac (with hose hooked to output side of vac) to blow the old coolant At first, I let the engine pump most of it out (I catch it in a bucket), then blow the rest out under mild pressure. This actually worked well (first time I've ever tried this).

Here's my crazy setup. No mess or crawling under van...
(my radiator doesn't have a petcock valve.. plus I wanted to remove what was in the block also).


I installed a New Stant Superstat #45358 180 thermostat
Note this thermostat is for a Gen1 V8 (not 4.3)
(I drilled the 1/8" bypass hole)..


The old thermostat housing had become surprisingly corroded...
(chrome flaking off caused a minor bit of leaking)


Here's the new one (from Summit Racing)...


It goes on with NO gasket (uses rubber o-ring).. works great.


The new 180 thermostat made no difference whatsoever!


So I still figured it's a "coolant flow issue", either the water-pump or the giant over-sized radiator.

So lets continue to go in order of easiest and least expensive first.
(even though it seemed unlikely to me the water-pump would be at fault)
There didn't seem to be much flow when I pulled the cap and watched the coolant level... so this seemed like a good move. The new hi-volume pump was only about $55... and labor was going to be easy enough.

The previous water-pump was new (2016) when I put in the V8. It was a GMB "hi-volume" pump. It obviously worked fine the first few years, so I wondered if it could have gone bad, especially with the harsh flushes I had done with the old internally rusty V8. I just wasn't sure if a water-pump could go bad internally or not.

I ordered a new one on Ebay (same model) ... GMB high-volume water pump.

The part number for "standard" pump is: #130-1620
The part number for "hi-volume" pump is: #130-1620P (performance)

The new pump arrived. But I got suspicious when I saw the pump body stamped with the "standard part number".. and the tag was ripped off the sealed bag. I contacted the seller regarding the issue, and they promptly sent a return tag and offered a full refund (incl shipping) no problem.


But before I sent it back, I contacted the GMB manufacturer and told them of my issue. They told me the stamp on the body is the same regardless of standard or hi-vol model, and that there was no way to tell the difference unless you opened it up, that the hi-vol model would only be different inside. I told them this was a terrible issue, that I had no way to know if I had received a hi-vol pump or not.

So I assumed I might as well just keep it, hi-vol or not (the previous same model worked fine or at least got me by)... I painted it, and got ready to install it. I did some research on high-volume pumps and learned they usually have a plate in them to increase low-speed pressure, and have other nice performance advantages. With a large than stock radiator, it's also called for.

When I pulled the old pump, I opened it up to see if it was damaged, but it looked fine (as far as I could tell..first one I've ever opened). There was no plate however. I did further research to be sure the fins were correct.. since this is a reverse-pulley pump. Direction was correct.


Then I decided to open the new pump.. and it looked the same! It should look the same, since the last pump was the same model part number. I started wondering if these pumps really are high-volume or not, since there was NO extra plate, and the fins looked pretty stock. Is this a con-game? .. and do they just put a different part number on the box, sell it for more, even though it's the same pump? Same stamp on the pump body. Who knows? Maybe the fins are a little different? I couldn't find ANYTHING online showing the differences.

New GMB high-volume pump:
(looked identical to pump I removed)


This really started bothering me! Why did I pay extra for a pump that looks stock, and may not be any better than stock. So I sent it back, and did some further shopping to see if I could buy an "actual" high-volume performance pump without spending a fortune!

I narrowed it down to two choices.. a toss up between "US Motor Works #US5049H" (performance pump, they also offer a standard model) or "Tuff Stuff Super-Cool" High-Volume Performance #1675N. Tuff Stuff boasted of using an actual plate in the design of their product.. US Motor Works did not mention it specifically (maybe just another GMB repackaged unit)... so I went with Tuff Stuff. Turns out it was only $65 at Summit (only $10 more than the GMB)... so I bought it.

Note: The pump is actually correct part number for my 92 Astro (reverse direction serpentine belt)


I had become obsessed with all this, and didn't want to guess or take any more chances.
Curiosity was killing me... so I opened it up!


Wow what a difference!
It's a US company that builds performance products.. and the pump looked GREAT!
Reviews were very good too.


The finish was beautiful too. It was unclear if I should paint it, or if it was coated (I couldn't tell). I contacted Tuff Stuff and their tech informed me the finish is raw, and should be painted. So I painted it with high-temp Rustoleum, then reassembled the steel back plate and heater hose plug (I don't use heat in South Florida).


They sent me this (the last letter on the part number apparently indicates finish)...

Tuff Stuff High-Voume Water Pumps.png

OK.. so this is what I'm working with! Note PLENTY of room (even with a V8) to change the pump, once the electric fan is removed out of the way! Here is picture of my work area and the old pump (just before removal)...


And the block cleanup (easy access between accy brackets)...


One more note... the bottom right hole is tapped into the water jacket, and pipe-thread tape or sealant should be used (only needed on this one bolt)...


New pump installed... (nothing too exciting.. lol)
Note: installed with dry gaskets as intended (always)


More coming...
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I enjoyed every bit of that, especially finally seeing the plate and the obvious benefit. A good cliff-hanger, too. Guess I'll be tuning in to the next episode.


Well let's just say I was a little disappointed when the thermostat made no difference, and I didn't see anything obvious wrong with the water pump (other than not knowing if it's TRULY a high-volume pump or not).

The massive oversized radiator I've been running is a 3-row all-aluminum Griffin Performance Radiator (used in Nascar racing) and it didn't seem likely to me that it could be bad. None the less.. it came from my 502 supercharged van (did an unbelievable job at cooling)... but is now about 25 years old! Regardless of size.. IF it has deteriorated internally or had become corroded or tubes clogged and blocked, it surely would perform poorly... possibly my case.

Unfortunately, I'm not going to know if the new high-volume pump fixed my problem, or the new performance radiator, since I decided to replace both. Essentially now, the entire cooling system has been replaced with everything NEW... BIGGER AND BETTER!

Here's a photo of the old massive Griffin radiator just before I pulled it...


I have been SO thrilled with the "Northern" custom over-sized race radiator that I put in my 2000 AWD.. that I bought another SAME identical model for this van. They are BOTH now running the same identical performance radiator, and BOTH running the SAME identical shrouded Flex-a-Lite electric fans. When things work this great.. you stick with them!

Here is the link to my 2000 AWD installation:

It arrived extremely well packed and in perfect condition!


The following I'll repeat (from my 2000 AWD installation post):



It's a "Northern Race Pro" #209615 31x19 high-performance "universal fit" radiator
(pictured with 8 plate internal cooler)


This is the same radiator re-branded for Summit-Racing, but I got a better price direct on Ebay for only $195 (incl free shipping). Like the Griffin Radiator in my 92.. this radiator is typically used in racing... and is extremely efficient at cooling under extreme conditions. Northern Radiator is a huge suppler of automotive, high-performance, hot-rod and specialty, diesel, agricultural, industrial, bus & large truck, ATV, air-boat and specialty products (as well as coolers, condensers, evaporators and so many other aluminum products)... and has a great reputation. This is one of their top models in their high-performance automotive racing series.

The 2 1/4" thick core uses 2 rows of wide 1" tubes.. considered a very efficient design.
It comes with a nice machined billet aluminum SAE compliant filler neck.

This model also internally incorporates a massive "8 plate super flow" oil cooler..
also somewhat overkill for my "street" needs (see above photo or click link): ... ERS/Z18039

This Race-Pro radiator is also designed to work with a cap pressures up to 28lb
I opted to use a slightly higher than stock pressure performance 20lb cap.


Here's a nice photo of the new radiator (obviously before installation)...
(I think my picture looks better than theirs.. lol)


I should note again that this is a "non-stock" universal fit performance radiator.
I do not recommend this for most people, since installation requires some modification and fabrication to make it fit. Not only that, but none of the stock hoses or lines fit either (even though that is fairly easily addressed). But it's NOT a direct fit. There are similar models (in other brands) made to fit the Astro perfectly. I just needed this to fit with a V8 as well, requiring fabrication and full relocation!

So here is my work area, and my "calm but anxious patient"... :mrgreen:


Below is another overhead shot of the old Griffin Radiator (just before I pulled it)
(Note it is somewhat tucked under the cross support.. engine and fan overlap and practically touch)
(click this or any photo to zoom)

20161022_194501-Radiator Engine 92.jpg

This new radiator is just a tiny bit larger, taller and wider than the Griffin (less than an inch or so), and required making a little more room for it to fit. It needed to sit a little lower to be able to access and remove the cap (an important big deal). I almost went with an elaborate "expansion tank" system, until I realized I could re-position and lower this radiator enough to make it fit. Again it was just an inch or so (a bunch of work) ... but well worth the trouble.

Not cutting metal... just "re-shaping" it... :D
(a little hard to swing a sledge-hammer in some spots)


This was some of the bracket system (1 of 2 stout aluminum brackets) I devised for the previous radiator, mounted to the lower radiator support. Very sturdy.. radiator just lifts off these supports. (underside view). The new lowered brackets are similar...


The upper cross-support had to be re-tweaked to fit and hold the radiator...
(just bending what had been previous cut to perfectly fit and hold new radiator)


Here's the new radiator being fitted (in and out dozens of times)...
(note nice rubber edge fitted on entire length of upper cross-support to hold radiator in place)
Bottom brackets are also fitted with nice rubber edges.. radiator literally just sits firmly in place.


It has been fitted in (even "more forward" than before).. almost completely under the upper cross-support. Here's an overhead photo (minus fan) with the new over-sized radiator completely mounted in place! Radiator is SO well tucked, it is almost invisible! :D


I now have a little more clearance (in front of the V8) than I had before.. plenty of room for electric fan!
Not a lot... but just a little more than enough!


This near-completed photo, you can see where it sits (essentially under the upper cross support)
(photo includes A/C condenser and external trans cooler)


I was unable to find a 1 3/4" > 1 3/4" lower hose that fit right (stock radiator side is normally 1 1/2").
This flex hose looked like a good contender, but kinked with the tight bend, so I was unable to use it...


The "stock lower hose" (shortened a little) worked (with Griffin radiator).. so it was re-used...


Note lower hose...


Even though the hose end is 1 1/2".. it can be stretched over a 1 3/4" outlet.
Stock lower-hose shape fit perfect!


I replaced the upper hose with "stock" new... trimmed 2" off each end to fit!
(remember V8 sits closer to radiator than V6 did)
The 1 1/4 hose had to be stretched over both 1 1/2 water-neck AND 1 1/2 radiator inlet.
(the hose MUST make a very tight 90 angle to clear the A/C compressor and serpentine belt)


As I mentioned... this radiator also includes a nice performance internal trans cooler (unlike previous radiator).
This required me to do a little hose re-routing to both coolers.
Trans > Radiator cooler > External cooler > Trans
Seen in this photo.. radiator, A/C condenser, external trans cooler, PS cooler (tucked low right)
Also note position of radiator literally against the front edge of the upper support.
It can NOT move ANY further forward.


Here are the oversized cooler 3/4 NPT fittings to barb 3/8 hose (sold separately)...


Another overhead shot (different angle.. mounted and almost completed)...


Final finished photo (not the best photo) ... but job completed (with hoses and fan installed)
(note edge of different carb in this final photo... that will be my next post.. lol)


This radiator runs a very solid 178-180 in my AWD (any outdoor summer temp)... never budges.
I haven't had a chance to take my 92 out on the highway yet.. I've currently got no place to go.

I'm also in the process of doing some other little upgrades (newly rebuilt Holley carb) and some minimal maintenance (rerouting vacuum lines, PCV, timing mods). I'm also installing new spark plugs, since they were new when I installed the engine originally back in 2014. I'm pretty much done.

Tinkering around the garage and driveway... taking advantage of my free weekends!

PS: Again, here is the link for the custom installation (with all the cutting) back in 2016..
(same as posted at top of page)

Cheers! :D
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Ok lol.. this is NOT part of the "new radiator or cooling system upgrades", but it's been part of the overall improvements and upgrades I've been slowly doing the past month, all going in together.

This part of the post is not really much of a deal either... other than it's just another slow day so I thought I would post some more story and photos!

Here's the old Holley 650 carb...


It was on the old 1970 350 engine (that's in my 92 Astro now) when I pulled it from my 69 Chevelle about 20 years ago. It had been on the engine since the 80's (and no telling how old it was before that)... so it is at least 40+ years old now, most likely older.

But I loved the throttle-response, the power, and the way it ran back in the day.. so I figured I'd give it another try! Holley's are GREAT performance carburetors! Preferred in single applications!

The ideal size for an efficient 350 engine turning a max of about 6000 rpms is roughly 600cfm.
Carb CFM Calculator: ... alculator/
Since this is a vacuum controlled secondary.. it yields ideal results!
Power-valves in these Holleys work fantastic too!

I started rebuilding this thing a few years ago (well mostly, and some of the rebuild kit (at that time) got misplaced, so I had to order another one. The carb had the original paper gaskets which were NOT coming off without a fight... chemicals and lots of elbow work too!


I wasn't sure if I had lost any of the carburetor hardware over the years either.. but it appears I found it all. It had got separated into several small boxes depending if it was primary or secondary side.

This was my first old Holley rebuild (I've done numerous Carter Edelbrocks which I used to run on my supercharged engines, or I bought them new). Normally a carb rebuild is a lot less dramatic! lol


Here's the Holley 650 (completed) next to my currently removed Edelbrock 500 (used to be 1 of 2.. part of a dual quad setup). The Edelbrock carb is also probably close to 35-40 years old too.. I bought it new (with it's twin) back in the 80's


Just for fun... here's the car I pulled the engine, trans, (and Holley carb) from...


And here's what the 350 engine (with Holley carb) looked like just before I cleaned it up and installed it in my van in 2014 (after sitting about 15-20 years or so)... lol

Just to show... you can't always judge by appearance!
I'd love to buy NEW carbs again, but can't justify the expense any more!
Plus they've gotten quite expensive!

I'm old school... I've been running carbs ALL my life!
My Astros are my first fuel-injected vehicles I ever owned.

The Edelbrock/Carter performance carbs are fantastic trouble free carbs! I highly recommend them!
The especially shine and perform well in dual-carb setups!

Here's a photo of the Edelbrocks (back when they were new on two of my different engines)...

Engines Both.jpg

I expect the Holley Carb to be a nice small improvement... especially (as I said) in a solo high-performance application.


So here's the most recent shot of the 350 in my van... (waiting for the carb replacement)
(photo taken this past weekend after new radiator and water-pump)


And finally the old newly rebuilt Holley rejoins it's original 350 engine companion!
The engine, TH350 shift-kit trans, B&M hole-shot converter, and carburetion all matched up again!
(I don't think I've ever posted an engine shot from this angle)


Like I said... slow day at the office! lol

Oh one more thing.. here's a quick video of it idling (with Holley)
(before timing tweak.. floats and idle mixture have not been fully set yet either)
It's actually idles better with the Holley than Edelbrock (more consistent in gear or with A/C on)

I still haven't had a chance to test drive with the new cooling system, or the rebuilt carb.
I'm replacing spark plugs tomorrow (they went in with original engine installation in 2014)
I'm taking advantage of weekends down time tinkering on my 92, while I have no gigs.

The Skip White HEI distrubutor is still relatively new, but I'll give it a "once over" too.
I've also made some timing changes.

The original 700R4 still waiting for repair (running temporary TH350)... that's probably next.
Broke a "hard part" in it.. but I'll rebuild all of it.

I still say the 350 engine in the 92 is temporary... as I have a pretty mean and more powerful 400SB sitting on the stand (also in photo above). The 400 needs some love.. but I haven't completely forgotten it.

I'll wash off the dust and spider webs.. then I'll likely take it out for a test drive and flex a little muscle and see how it does. Then back in the garage while I start on next projects...

That's it! :D
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Goodness... just love that blappety, blap...blappety blap, even with stuff to tweak.

Sitting at the light ... :whistle: SWEET. Thanks, Scott - V6 never gonna' sound like that. ( sorry, Randy )
I love the van but that Chevelle made me all tingly! I had a green 69 Malibu. I put in a 327 with an Edlebrock performer intake and cam set and a Holley 600. It came with a 307 but it smoked like a mosquito truck.

I also had very similar wheels to yours. Mine were Enkei 20s and I don't remember the tires other than the rears didn't last very long. :D

Thanks for the excellent write up and the fond memories!
You never disappoint! :cheers:
Bikley said:
I love the van but that Chevelle made me all tingly! I had a green 69 Malibu. I put in a 327 with an Edlebrock performer intake and cam set and a Holley 600. It came with a 307 but it smoked like a mosquito truck.
Actually, my story is almost identical to yours!

I actually had two 69 Chevelles (my first one also originally green but repainted white), one hard top & one convertible (the green interior of the hardtop made me want to My 69 Chevelle Malibu convertible (in photo above) ALSO came with a crap 307 (well they both did..I call them "dumpster motors".. because that's where they both I also put a 327 4bbl in it (which had come from my former 69 HO posi-traction Impala).. but eventually threw a rod (only time I've ever done that) with that engine racing it. It had blown a gasket and the oil looked like a milk shake. It was clearly on borrowed time and I knew it. Back then V8 engines were a dime a dozen, and a 327 was still a little small for me... so it didn't matter (only one I ever owned). I used to pull engines like some people do oil changes.

Then I finally bought (back in the 80's) a very low mileage 70 Caprice (for $200) that had ONLY about 30K on it (a little old lady actually had owned it). The car was a tank and even though in excellent condition, I only bought it only for the 350 engine and trans, and sent the car to the junkyard. I put this 350 in the Chevelle (drove it for many years)... and is what I'm now using in my Astro today.

Oddly enough... for some reason I put in an Edelbrock Performer Kit (which I never normally do). This kit included an Edelbrock Performer intake, as well as a pretty radical street Edelbrock camshaft, lifters, and springs kit. I had never bought an Edelbrock cam before (always Crane, Comp Camps, Erson).. and this cam was quite a surprise! The motor REALLY came to life! I was so curious recently I had to go back (found the specs) to see what it was. It's a little more cam than I would buy today, although the same grind might be ideal for my 400 (although it's currently running a roller Comp Cam). As stated, it's one of my next projects. The low-mileage trans was like new, put a B&M shift kit and new B&M hole-shot converter in it, and here I am today. I can't remember where the Holley came from.. maybe the 327 (if so would make it 50+ years I don't remember ever buying it... or I'd probably still have

Thanks for the excellent write up and the fond memories!
Thank you.. my pleasure!
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augidog said:
I enjoyed every bit of that, especially finally seeing the plate and the obvious benefit. A good cliff-hanger, too. Guess I'll be tuning in to the next episode.
One of my specialties... turning a basic water-pump installation into a "thousand word story" (at least with pictures).. lol

sixsix said:
Goodness... just love that blappety, blap...blappety blap...
Sitting at the light ... :whistle: SWEET. Thanks, Scott...
Rumbling at a traffic light is just about as fun as cruising! lol
Taking off (even when I'm usually easy on the throttle) is even better! :D

CopperFiremist said:
You never disappoint! :cheers:
Thanks! I enjoy sharing what I can.
A little long maybe.. but hopefully the pictures broke it up a little.. lol
I do some of this for my own reference too, so I can refresh my memory years later on what I did.. part numbers, etc.
Two things worth looking at for over heating are timing/vacuum advance and air fuel ratios. If either are off you can run hot. More likely in varb engines than efi because of integrated timing control.
Definitely interesting to see the difference in the pumps, wonder now how many are actually high flow. Should always at least get what is advertised.

Mmusicman said:
The new 180 thermostat made no difference whatsoever!
The thermostat only determines the minimum normal operating temperature. Unless of course it has failed shut or something like that.

Mr_Roboto said:
Two things worth looking at for over heating are timing/vacuum advance and air fuel ratios. If either are off you can run hot. More likely in varb engines than efi because of integrated timing control.

With that huge radiator in there before, if there wasn't a coolant or air flow issue then you definitely should not have been having over temperature issues without something wrong with the engine. At highway speeds you aren't going to be having air flow issues without the radiator being clearly blocked in a big way.

Have you ever run an o2 sensor to tune?
Timing was correct.. air/fuel same as it has always been.
The new cooling system appears to be working excellent.


Well this is pretty much it for this project!
Pretty much just going over all the little things now...


I figured it might be a good time for a plug change.. the plugs were put in with the original V8 installation back in 2014 (and reused for the 2016 re-installation)

For future reference.. I've been using Autolite #26 (for about as long as I can remember)


The old plugs...

Rotation of 20200425_143708.jpg

Coincidentally, I just changed out the plugs in my wife's 99 Honda Passport too.
These were her ORIGINAL plugs.. 21 years old with about 160K on them!
They actually still looked surprisingly good. Her engine has no distributor.


I also figured (while all my plugs are out) I'd give the cylinders a once over with a compression test...


Everyone passed (close enough)...


Plugs change is a piece of cake (even with headers).. I used a box wrench.
Compression test however, is a little bit more work.

Oh, I also checked pulling each cylinder running (for rpm drop)
After getting shocked (even wearing gloves) .. this was my makeshift plug wire puller.. lol
No more shock! :shock:


Like I said... slow day at work (and today is no

My distributor cap & rotor looked great, linkage good, wires good, vacuum good.
Tightened all the header bolts.. they needed it.
Valve covers needed some tightening too.
All just general follow-up.. haven't had the cover off in a while.


Front view (all done here) ....


Tightened the exhaust collectors bolts...
All else underside looked good...


Not pretty... this how it ALL "actually" looks when I lift the hood... lol


Finally... I took it around the block for a quick test drive. This wasn't intended to be a full throttle burnout blast.. just moderate acceleration (checking shift point and throttle response) for regular driving. (I need to do a full throttle blast video one of theses days soon)

It's an early automatic shift (selector was in drive) in this video (kick-down linkage sticks and is disconnected) and 1>2 I let off the throttle a little early... but hey it is what it is! lol

I'll get a more exciting video next time! Like I said just a casual test. I need to set a camera up in a fixed position instead of trying to hold the phone while driving and shifting.. lol

Need to get a new kick-down cable (even though the TH350 trans is temporary).. and get a new throttle cable while I'm at it (the old cable came from my 74 van.. and it's time for a new one)

I've followed my wife driving this van, and this is how it shifts for her too.
But she got a kick out of it (no pun intended)
Vacuum modulator is adjustable.. may have to back it off some more.
No worries with the TH350, but we'll see when I go back to the 700R4.
Don't forget, I'm carrying a van load of sound equipment too.

The engine temperature didn't budge... stayed rock solid at 175-180, but I didn't go too far.
Hopefully soon I can get it back out on the highway!

Fun while it lasted...
Back in the garage... back to my 2000.

That's it! :D
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ought to be a law... :driving:

side note: that IS your A/T dipstick right there by the dist... right? Glad we don't have to check that level much.
sixsix said:
..that IS your A/T dipstick right there by the dist... right? Glad we don't have to check that level much.
Yes it is.. good observation. My 700R4 I still use the stock filler tube (even with the V8 engine) that is accessible from the front, but the stock tube doesn't fit the TH350. I bought a longer chrome universal tube for the TH350... but it's bracket arm didn't match up which really annoyed me. So I grabbed a short one I had laying around and stuck it in.

Yeah.. it's a good thing we don't have to check the trans regularly.
Wow Thank you, for all you do.
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