Sprinter 4WD Conversion Idea, GMT-800 IFS.

[luthj]

I will post some pictures up later, but mostly finished going through the sprinters trans. Except for the valve body.

Minor to moderate wear on the K2/B3 inner drum. I will use the donor unit.
Moderate wear on the center roller bearing (front/rear shafts)
Moderate wear on the B1 shaft bushing.
B1/stator drum shows minor wear, a bit of a groove from the cushion plate.
B2/B3 outer drums are fine.
Pump is good, I will use donor, as its tighter.

Clutch disks were all in good shape. Some minor wear ridges on the backing plates on the B1 and K2 sets.

Differences between the Jeep and sprinter trans.
All clutch buildups were basically the same. The K1 on the sprinter lacks the apply plate. The B1 has 2 extra frictions on the sprinter. I would have preferred to use the jeep stator, but it will only accommodate 6 frictions.
The jeep trans uses a different sized cable ball on the shift shaft. It also uses a different shift cable mounting bracket. I will need to modify the sprinters bracket, or swap cable/ends. Shouldn't be a huge deal, and the boss for the third mounting bolt is cast, but not tapped.

 

[luthj]

Here is a good example of the wear differences. Bottom is low mile jeep grand cherokee. Not sure how low, but the engine seized due to low oil. Top is from the sprinter.
The right side splines are the K2 clutch, the left is the B3 clutch. The K2 clutch is the most used, and sees more high torque applications than the other clutches. Its usually the first to go when abused, and the first to wear out.

 

[luthj]

I reassembled all the clutch stacks and checked the clearance. All are good, so I won't be replacing any of the plates.

here is one of the wear points. I guess pushing around 9k lbs does make a bit of difference.


Here is the Different B1 stacks. Interestingly, I could not find the 8 friction stator housing in a brief search. Must not be a common config.





Its mostly a really expensive puzzle. As a plus I have plenty good used spares in case if mess something up.


I will try to find time this week for the valve body. Based on the mild symptoms the van had, I expect to find some wear in the main pressure valve, and crossover valves. Depending on what shakes out, I may go with the donors valve body. Its quite time consuming to clean sadly.

 

[Mwilliamshs]

With the intermediate shaft allowing minor misalignment, there isn't much load on the output shaft bending wise. I will give that area a good look, but I don't think there is much risk compared to the other common 4x4 transmissions, where the output shaft mates directly with the Tcase input gear.

The load needn't be bending for that hole to be a concentration of stress. Deburr it well. Keep moving. Nothing to do about it now and like you said, you're not bolting that trans to a fire-breathing torque monster.

 

[luthj]

Tore down the valve body. Pretty clean, but I change my fluid every 50k or so.





Got most of the parts degreased and cleaned up.



Preliminary inspection looks pretty good. No wear on the pistons, no broken springs. Mile wear on the end plates. I need to get my inspection light in the bores. The 2-3 and 4-5 overlap sleeves show some wear. I may order replacements depending on cost. Check balls and screens look good.

On the to-do list is to pressure and vacuum test the solenoids. I still need to decide if I want to get a refurb TC or not (about 225$). There was some minor fiber debris in the TC. It was fine enough that a medium paint strainer didn't pick it up.

A friend found a compatible 1350 slipyoke, so I all need in the rear flange yoke, and I an order my driveshaft once its all back together.

 

[luthj]

Went through the valve bores on the valve body. A bit of wear from the springs, but the bores look okay. The overlap sleeves were showing significant wear on the 3/4/5 valve sets. So I ordered a new/improved sonnax set. Some engineer at MB was smart enough to make the highest wear part separate from the valve body casting.

I got my seal kit today, and it looks complete enough for my purposes. Tomorrow I will go through and replace all the seals. Except the piston seals themselves (all by the B1 use O-rings). Removing the retaining rings is a pain, if the clutch packs don't leak excessively, I will just leave them alone.

I have attached some info the NAG1 torque converter variants. I was considering swapping for a later version with internal damping springs, but that would require swapping the NCV3 flex plate. It should bolt up, but there may be bell housing differences.

 

[luthj]

Put a few hours into the trans. One last parts order
Output shaft bearing
Vent tube fitting
Reman Torque converter

Solenoids are hard to flush properly, as they become magnetic over time, and pick up ferrous particles.


Resealed the pump. Clearances were good.





The B1 housing bushing was a bit worn on the sprinter. The Jeep donor has the snap ring too low, so I can't use it without sacrificing some torque capacity. I re-used, as a 5 friction pair unit is unobtainium for non dealers.


I spent 30 minutes trying to figure out why the B2/3/K3 stack was too long to fit the snap ring. took it apart 20 times... Turns out I had stacked two thrust bearing races. Easy to do when you have 2 transmissions on the bench!




Theres the whole stack, minus the B2/3 housing, which bolts to the case.


Swapped in the sprinters shift level. Interesting, the detents on the internal lever where slightly different. The sprinter had deeper ones on drive and park.


Now its ready to set endplay with shims, then I can install the bearing and output seal. The valve body is next up, but I can't finish it until I get a few more parts next week.

 

[luthj]

Vaguely mechano-sexual? Maybe. without 37" tires, it can't be expo-sexual, I think?



Valve body is mostly back together. Good thing I have a spare, as I lost 1 spring somehow, and it turns out there are 5 spring lengths, and 4 spring sizes. Some only about 5mm different in length. Next Time I will measure them as they come out!



The sprinter uses a longer shift lever, and different cable bracket. One of the mounting locations has an untapped casting nub, the other two were deleted. I tapped the lower nub, and I will weld a cross brace to the (shortented) mount points for the Jeep bracket.

 

[shade]

Are you just grunting a lot, or do you have help moving that around?

 

[luthj]

Jen helps me when I need to move the big bits. The trans I build in place. Its too heavy for me to move on my own, at least off a dolly. The Tcase is just light enough on its own. Once they come together for the last time, its going to be fun getting it all under the van, and on the trans jack....

Last thing I need is to throw my back again...

 

[shade]

Jen helps me when I need to move the big bits. The trans I build in place. Its too heavy for me to move on my own, at least off a dolly. The Tcase is just light enough on its own. Once they come together for the last time, its going to be fun getting it all under the van, and on the trans jack....

Last thing I need is to throw my back again...

She continues to impress.

If you don't have one, Harbor Freight sells a few transmission jacks. I see people buy engine hoists and the like, use them for one project, and quickly sell them for a little less than whatever fire sale price HF is running.

HF also sells surprisingly less than awful chain falls that may help with positioning that stack on a jack.

 

[luthj]

Yep, I got this (kinda crappy) trans jack from HF 5 years back for 75$. Its paid for itself a few times. The 450lb limit is a joke, as you need a 4ft breaker bar to get the much weight moving.

450 lb. Low Lift Transmission Jack

Amazing deals on this 450Lb Low Lift Transmission Jack at Harbor Freight. Quality tools & low prices.

www.harborfreight.com

I need to get some wood blocks for my jackstands. The rockers are about 18" from the ground, and the bell housing is ~17" tall. So I may just slide the assembly on some cardboard, and then find a way to get it on the jack under the van.

 

[shade]

I need to get some wood blocks for my jackstands. The rockers are about 18" from the ground, and the bell housing is ~17" tall. So I may just slide the assembly on some cardboard, and then find a way to get it on the jack under the van.

Corrugated plastic sign board works great for sliding in tight spots. I actually prefer using that over a wheeled creeper. If there's an election between now and final assembly, I think you'll be able to find some without too much trouble.

 

[luthj]

I am hoping to get this lump mounted up in 2-3 weeks. I do have some scrap coroplast/twinwall . Put that over some cardboard may be the ticket.

 

[Stevemo]

Be sure to install a new conductor plate, they get covered in metal gunk causing speed sensor problems. Dorman sells replacements that are repackaged Mercedes parts. Mercedes charges a core for them for some crazy reason so be sure not to buy one from them. I haven't read through much of this thread but I assume you have a NAG1 out of a diesel Jeep WK. They require ATF+4 as there are some differences in components but atleast they are the German made transmission. I believe the gas model Mopars had different NAG1 transmissions that used a different conductor plate than the German ones.