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New to AWD-questions-RC98

PostPosted: September 6th 2020, 4:44pm
by markmitch
OK so to start I will tell you about the van as much as I can. It is a 1998 AWD cargo it needs a transmission what I need from all you is a bit of guidance. I want to go through the systems while I look for a used transmission. Such as the front and rear axles and the transfer case. I know what to do for the rear axle but no clue on the front axle or the transfer case. Should I drain them both and just refill? is there a filter in the T-case of any sort? what fluids go in the tcase and the front axle? What should I be looking for as far as possible problems Any other AWD problems I may encounter? . Future plans are to do the 4x4 t case swap but I need to get whats broken fixed first. Any front suspension items I need to look at? Thanks in advance. Mark My 89 is called 1st-gen this 98 is called RC98 (wife's initials and the year since its hers).

Re: New to AWD-questions-RC98

PostPosted: September 6th 2020, 5:35pm
by dit
ATF in the t-case and whatever gear lube you run in the back do the same up front. Check upper and lower ball joints and axle shaft seals.

Re: New to AWD-questions-RC98

PostPosted: September 6th 2020, 6:23pm
by M_a_t_t
I believe Leeann always recommends autotrak II for the t-case. Maybe she will stop by and verify.

Re: New to AWD-questions-RC98

PostPosted: September 6th 2020, 8:10pm
by dchan51360
on a 98 which is a transition year, (some BW 4472 and later was NP136 or NV136)

So first you need to know which xfer case you have. If it's the BW 4472, that uses standard ATF fluid. Currently no rebuilding of those. No more parts available unless someone started building new ones.

If it's the NP136/NV136 You do need to be running Autotrak II

You don't want to contaminate the clutch pack in either. especially the BW 4472. The rebuilt/aftermarketn 4472 clutch pack is horrible. It took 3 replacements to get mine to function properly before I finally sent the 97 to the JY.

If there are no wires/connectors to the xfer case, you have a BW 4472

If there is a cable/connector on the xfer case, it's an electronic AWD and you have a NP/NV 136

Or since you need to replace everything anyway, maybe you should just consider going with a 4x4 conversion!

Re: New to AWD-questions-RC98

PostPosted: September 6th 2020, 8:12pm
by dchan51360

Re: New to AWD-questions-RC98

PostPosted: September 6th 2020, 8:45pm
by dit
Didn't know some 98's had the 136, good catch.

It's been many years since I pulled the 4472; it does have a VSS harness (i.e. wires) to it as I recall :think:

Re: New to AWD-questions-RC98

PostPosted: September 6th 2020, 10:02pm
by markmitch
The transfer has a small plug going to it with two wires so its a two prong plug at the top passenger side of the transfer case. I did not see any other wires or cables and no ID tag unless its a strip of sheet metal but it was to dirty to read and its 100 and climbing so I can try again in the morning. Thanks for the answers.

https://www.astrosafari.com/viewtopic.p ... 2#p1561282

Re: New to AWD-questions-RC98

PostPosted: September 6th 2020, 11:03pm
by dit
A photo would help! If it has a large disk like this on the front output shaft it's a BW ***note the TC in this image is upside down***
Screen Shot 2020-09-06 at 3.00.13 PM.png

Re: New to AWD-questions-RC98

PostPosted: September 6th 2020, 11:38pm
by markmitch
yeah I think that is what is in there so what is the best 4x4 transfer to use I will most likely use the kit from journeys so I can do it kinda quick. I am patient but I think if I take to long my wife may lose interest and therefore not want to be buying stuff for it after a while. This building for my wife idea is also new to me lol.

Re: New to AWD-questions-RC98

PostPosted: September 7th 2020, 2:51am
by Leeann_93
Yeah, autotrak 2 only for ā€˜99 and up (and the very few late ā€˜98 vans that got the NP136).

For the BW4473, Dexron is the stuff. No filter. Front and rear diffs, gear oil. I use Mobil 1 75w90 or Valvoline 75w90, whichever I get my hands on, unless Iā€™m going to either tow or haul heavy loads, in which case I put 75w140 in the back and 75w90 in the front.

Re: New to AWD-questions-RC98

PostPosted: September 7th 2020, 8:52am
by maximus7001
Be sure to put the posi additive in the rear if you got the G-80 LSD in there. Mine has it. The front diff is open so no additive required. You can get a bottle of the additive at the GM stealer at the parts counter.

Re: New to AWD-questions-RC98

PostPosted: September 7th 2020, 3:25pm
by Leeann_93
Both the Valvoline and Mobil 1 have the additive in them, no extra required.

Excellent limited-slip performance - Helps to reduce chatter and improve traction

Re: New to AWD-questions-RC98

PostPosted: September 7th 2020, 3:32pm
by dit
maximus7001 wrote:Be sure to put the posi additive in the rear if you got the G-80 LSD in there.


From my understanding limited slip additive is a friction modifier for clutch type differentials. The G80 has no clutches, it is a flyweight design. The Eaton TruTrac also doesn't benefit from the additive being that it is a geared LS.

Re: New to AWD-questions-RC98

PostPosted: September 7th 2020, 3:54pm
by dit
markmitch wrote:what is the best 4x4 transfer to use I will most likely use the kit from journeys so I can do it kinda quick. I am patient but I think if I take to long my wife may lose interest and therefore not want to be buying stuff for it after a while. This building for my wife idea is also new to me lol.


This would depend upon what kind of off highway driving your wife likes to do. If she doesn't need low-range, why bother? I found the BW t-case is excellent for all conditions other than crawling. Being a viscous clutch it can and does wear out, mine never did.

Re: New to AWD-questions-RC98

PostPosted: September 7th 2020, 8:21pm
by AstroWill
maximus7001 wrote:Be sure to put the posi additive in the rear if you got the G-80 LSD in there. Mine has it. The front diff is open so no additive required. You can get a bottle of the additive at the GM stealer at the parts counter.


You should NOT add ANY additive into our rear ends, the G80 RPO codes on our vans aka the Eaton M-locker, is not a limited slip and it can cause issues/damage, there is even a TSB about it.
It's not a limited slip like they put in the cars under the same G80 RPO code.

Re: New to AWD-questions-RC98

PostPosted: September 7th 2020, 8:30pm
by markmitch
I actually have read what Astrowill spoke of so i disregarded it but thanks for all the info. As for the 4 low we do need it in New England since one driveway is a hill and dirt which is the driveway to the cellar of the barn which is where my shop will be. I already got a wood stove, a pellet stove and 12 fluorescent lights free from someone that is moving.
I have someone looking for a lift to put in after the 1st floor ceiling is cut for the lift. Either way all this is future stuff and depending on life may or may not happen. Its ok to dream as long as it does not ruin your real life is what my mom used to say.

Re: New to AWD-questions-RC98

PostPosted: September 7th 2020, 8:45pm
by AstroWill
markmitch wrote:I actually have read what Astrowill spoke of so i disregarded it but thanks for all the info. As for the 4 low we do need it in New England since one driveway is a hill and dirt which is the driveway to the cellar of the barn which is where my shop will be. I already got a wood stove, a pellet stove and 12 fluorescent lights free from someone that is moving.
I have someone looking for a lift to put in after the 1st floor ceiling is cut for the lift. Either way all this is future stuff and depending on life may or may not happen. Its ok to dream as long as it does not ruin your real life is what my mom used to say.


You would be surprised how well the AWD works in our vans. I never, ever had a problem with my AWD vans in ME. Maybe give it some time, throw a locker or limited slip in the rear if you find that the AWD isn't sufficient.

All options, gotta go with what you feel is going to be the best for you.

Re: New to AWD-questions-RC98

PostPosted: September 8th 2020, 12:32am
by sixsix
AstroWill wrote: ... the G80 RPO codes on our vans aka the Eaton M-locker, is not a limited slip ...
It's not a limited slip like they put in the cars under the same G80 RPO code.


Hope you don't mind me commenting...
Will, I was not aware of that ( not that it applies to me, just curious ) - same RPO - G80 used for 2 different rear end innards.
And... being different from the auto application. Interesting.