Removing the front differential assembly for repair while keeping the truck drivable?

[StarquestMan]

The 4wd in my 88' MightyMax has been out of commission for about a year now due to what has to be a bad pinion bearing. I ordered what I hope is all the needed bearings and seals to get it up and functional again. I had the idea of just dropping everything out as a unit and leaving the cv axles and front driveshaft in the truck and doing the repair as I get time. I would think I would be able to use zip ties and wire to keep those parts secured out of the way enough that I would be able to use the truck in the meantime. The hubs should remain unlocked I would think, and the front driveshaft slip yoke could be secured to the transfer case so it doesn't just slide out and dump all the oil out. I think the cv axles are held into the steering knuckles with a snap ring if I remember correctly. The service manual showed everything being removed including the steering knuckles, but I don't think I would have to do that, right?

I have read one of the older threads on here talking about using a starquest differential in the front ends of these trucks. I just happen to have an 86' TSI parts car that I could pull one from which would probably be quite a nice addition while I have everything apart, I would just have to swap the ring and pinion onto it so it would be the correct 4.222 ratio for my truck.

any flaws in my logic here? I think everything sorta checks out?

[FMS88]

Interesting proposal. I don't know about using the Conquest ring and pinion, but a part number search might provide some insight.

Separating the yoke from the front drive shaft and securing it to the transfer case so it can't vibrate out should be fine. But leaving and suspending the CV axles somehow seems risky. Backing up might lock in the auto hubs which would be a problem. As an alternative why not remove the axle snap rings and remove the axles? No need for wire and zip ties then.

You don't need to remove the knuckles. Remove the right axle by unbolting the inside end from the differential flange. On the left, pry the inside end out of the differential. This usually requires separating the upper ball joint, but since you're removing the differential, it might be possible to separate the axle from the differential when the differential is detached and ready to lower. This way the alignment is unaffected.

You will have to fashion a cover or something to prevent water and dirt from entering the axle bore in the knuckle. Also remove the brass spacers so they don't fall out or get lost.

[StarquestMan]

Thanks for the reply, sorry to just get back to the thread, I've been super busy. I think I sort of mis spoke about my plan for using the differential from the Dodge Conquest. I would only be using the carrier out of it since it is a TSI widebody car with the limited slip. I don't think anything else like the housing or mounting is interchangeable between the two vehicles since they are very different from each other. As far as I know there never was any LSD options offered from the factory for the front differential in our trucks, only the rear axle could get the LSD. The post I read was saying that the carrier used in the Conquests and Starions is smaller than the ones used in the rear axles of the trucks but was the same size as the ones used in the front differential of our 4x4 trucks. This seems like it would be an awesome upgrade for my truck since both differentials appear to be the standard open type.

I don't really think I can use my parts catalog to confirm anything though since it doesn't really show any specs on the parts themselves, just part numbers and the factory interchange of what was offered originally from them. since the LSD carrier was not used in the front of these trucks it won't show up in the list. I think I'll probably just have to pull both of the carriers out and see if it will work.

This brings me to another question about compatibility, I don't know how it will work with auto locking hubs! The part that is currently causing my 4 wheel drive to not be usable is the pinion bearing and its failure brings an interesting symptom that makes me question if an LSD will even work with the stock auto lockers!? As my truck sits now, I can shift it into 4wd and it will somewhat work. It binds up badly if I try and turn and drive at all with the 4wd and hubs engaged. Things get very interesting once I take it out of 4wd and try to move forward or backwards. One or both hubs are supposed to be able turn the differential maybe a half turn or something as the truck moves in the opposite direction so the hubs are able to unlock themselves. Normally the ring gear can spin the pinion gear as this happens but since the bearing or bearings that keep the pinion gear aligned properly with the ring gear are shot, I think the two gears are binding up. This makes the front wheel or both front wheels lock up and keep the truck from moving at all unless I get out and crawl under the truck to turn the CV axles backwards to unluck the hub manually. This makes me wonder if having a LSD for the front differential would even work? I would think the whole ring gear turning the pinion gear situation will be fixed when I replace the bad bearings, I'm just not totally sure that adding an LSD carrier while I have everything apart won't cause some similar problem for the hubs unlocking themselves when I go to shift out of 4wd.

[FMS88]

I think I'll probably just have to pull both of the carriers out and see if it will work.

Definitely agree. I doubt few if any have tried an LSD in the front, but it will be interesting to find out if the truck housing can accommodate the TSI/LSD carrier.

As to compatibility with the auto hubs, I can't think of any reason why the hubs would engage and disengage differently if the lock and unlock procedures are followed. Once the differential issue is repaired, I'd expect the auto hubs to perform as expected.