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Discussion Starter · #1 ·
Simple question, maybe not a simple answer...

I have a 1990 4L60 (not 4L60E!) in my 90 Safari. Having some issues, but I have an earlier (late 80's?) 700R4 with a cable speedo drive.

Aside from installing a reluctor in place of the plastic speedo gear, are there any other issues?

I know most swaps are later trans into earlier vans, but I haven't found anything definitive on using a slightly older trans in the 90.

Any input would be appreciated....
 

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Basically the same transmission. Slight difference in the gearing but no big deal.

Just don't use an early to mid 80's 700R4 as they were prone to input clutch drum failure. Unless you get a reman and know the clutch drum was upgraded. Since you already have your late 80's unit, no need to worry about that. Swap away !!!

Just make certain you install and adjust the TV cable correctly. If not, many a 700R4 have been fried that way.
 

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I said slight difference, basically none worth mentioning performance wise. I remember years ago reading some had modified input clutch assemblies installed with different planetary gear assemblies for severe duty applications. Couldn't tell you which ones though.
 

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2000 Lifted 4x4 Astro 92 V8-350 Shorty
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No, not confused. Plus I'm not worried. Never have and never will. We need not agree on everything all of the time. The nice part about this country - for now. As I said, only know what I read. I don't know everything about transmissions and never will, nor care to. Just sharing thoughts and ideas based on experience. If you disagree with someone, it's not a big deal. I really don't care whether someone agrees with me or not. I just try to help people out when I can.
 

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2000 Lifted 4x4 Astro 92 V8-350 Shorty
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If you dispute the information in the link I posted.. then show us
 

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2000 Lifted 4x4 Astro 92 V8-350 Shorty
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Otherwise don't feel bad.. I've been corrected a time or two as well.
It happens (often its something dumb too)
 

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Yes, I saw that link. Yes from the factory, they are the same. I don't dispute anyone's information nor did I post incorrect information. The two transmissions are nearly identical, yes. I did not explain clearly enough in the original post. Yes you are right and yes I am right. But some 700's had 5 or 6 gear planetaries installed for increased low end power transmission i.e. heavy, severe or performance duty. They were AC Delco parts and are still available. When and where and who installed them or what they were installed in, I have no idea. Could have been factory, could have been aftermarket or upfitter. But exactly whom, don't know. Yep have been wrong many times before, will be again, and when I am wrong I will gladly admit it - but not this time.
 

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2000 Lifted 4x4 Astro 92 V8-350 Shorty
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SERIOUSLY??? LOL
Repeating yourself doesn't make you more right either.
I can't make it ANY simpler for you..

"Slight difference in the gearing" but no big deal...
when I am wrong I will gladly admit it - but not this time
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Now I know you're just trolling... I'm done.
 
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Common Sense + Critical Thinking
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Maybe one of you is referring to gearing as the gear ratios and the other is referring to gearing as any of the gears in the transmission.

So, the gear ratios are the same but some of the gears could be different, sounds about right.
 

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Yes, unless you have one which had the modifications I mentioned. I can't make it any simpler then that. Sorry. Don't see how this is helping this guy with his swap anyway, unless he wants one with the lower first gear.
 

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Discussion Starter · #17 ·
Okay, enough about you...let's talk about me....!

So, I'm finally actually doing the swap this weekend. A couple of false starts and winter weather delays.
As to my original question, can I swap a late 80's 700r4 in place of a 90 4l60....like everything else, yes. And no.
Yes, you can do it. No, it's not a straight swap....sometimes. The devil is in the details and he and I have been toe to toe.
It's been a little trying to tease this info out of the internet.

Mainly the details that cause a complication are in the tailshaft extension housing. The speedo drive, for one. There are three types of speedo drive. One is mechanical, with a cable and a plastic gear mounted on the output shaft. A second is the magnetic sensor VSS with a 40 tooth metal reluctor on the output shaft instead of the plastic gear. There is apparently a third one that appears to be a hybrid (plastic drive gear like the mech speedo, but converts to an electronic signal...or something like that...didn't really investigate much as it's not relevant to my situation).

Anyway, my 4l60 in the van has the VSS and reluctor. The 700r4 has a mech speedo. My van has the so-called analog dash, which isn't really analog. It uses the signal from the VSS to generate a signal for the stepper motor on the speedo. The optional digital dash is...digital and probably uses the same VSS sensor. Personally, I would consider the mechanical speedo to be truly analog.The extension housings are the same...they accept both the mechanical cable housing or the VSS sensor. But I have to install a reluctor wheel onto the 700r4 output shaft. The reluctor was $23, cheap enough that I bought a new one instead of trying to get the old one off (plus, I could prep the new trans without disassembling the old one. The van stays driveable in the meantime). This way I could also confirm that the reluctor would fit on the 700r4 shaft as I could not find size dimensions for the plastic gear, the reluctor or the shaft. Remove the extension housing, remove the plastic gear, heat reluctor ring up to about 300 degrees and holding it with channel locks it slid right into place, no hammer. It is a little narrower, so make sure it is centered where the plastic gear was and centered in the hole in the extension housing. That's one thing down.

The second item is the yoke sleeve. Some transmissions with have them, some will not. It is important...kind of. It goes on the output shaft after the speedo gear or reluctor gear. It is a large metal sleeve about 5" long. The purpose of it is to seal the driveshaft yoke. You would think the rear trans seal would do that, right? Well, it does. Unless you have a vented yoke. If you do, there is nothing to prevent trans fluid from getting in to the yoke by way of the yoke splines and leaking thru the yoke vent. So the yoke sleeve has a rubber o-ring inside the open end to seal the yoke from the trans fluid. If you do not have a vented yoke, no problem. How do you tell if you have a vented yoke or not? I don't know and I don't know if I have one either, but this trans was in my 86 Safari for awhile and it had the yoke sleeve on it, so I'll reinstall it. I'll know more about vented/non-vented yokes once I get my driveshaft out.
To swap speedo gears/reluctors, you have to remove it first. It is a press fit. I used a pair of channel locks to rotate it to loosen it (grab it on the closed front end, not the open end!). Once loose, I used the channel locks between the closed end and the speedo gear and tapped on the channel locks to drive it off. Not difficult at all. You do have a little leeway with placement when reinstalling. I would try to be exact, but if you are a 1/16-1/8" off, I don't think it will matter.

My 700r4 trans turns out to be an 86 if I read the codes right. The 90 torque convertor fits the input shaft just fine.

I think some of my issues figuring out this stuff comes from the fact that because these transmissions are swapped into lots of older cars, most info is generally for swapping and incomplete or of unknown relevance to a stock application. It is actually hard to find exact info on what is right for a specific year and model and how it relates to another specific year and model. Like the reluctor. It is listed on a transmission parts website as 93 and newer trucks and 94 and newer cars....so why is it in my 90? Because it is and they are wrong. Other places say 87 and later.

I will get part numbers later, but this is the list of parts I have put in it, some just because it's easier now and some because I had to:

-input shaft seal (small o-ring about 1/2" diameter...seals something in the torque convertor)

-front transmission seal

-rear transmission seal

-VSS reluctor

-yoke sleeve

-yoke sleeve seal

-extension housing seal (square cut seal between extension housing and main case)

-Lockup solenoid

-filter (always check for old seal stuck in trans before trying to install new filter with seal)

-new torque convertor
 

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Yes, unless you have one which had the modifications I mentioned. I can't make it any simpler then that. Sorry. Don't see how this is helping this guy with his swap anyway, unless he wants one with the lower first gear.
What are you talking about?
4L60, 700R4, and even 4L60/65E have identical gear ratios throughout all gears.
 
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