I swapped a 5 speed from a 87 GL in place of a 4eat into my 90 loyale. I am having problems with the 4 wheel drive and it is being caused by the rear dif. I have not driven it more than a few feet as to not damage anything. When I swapped out the auto could that have changed the gear ratios in the front but not the back? How do I tell the gear ratios of the rear dif and the 5 speed tranny, is there a place that will tell me. Also it could be that the dif is shot because I know that it leaks fluid, but it did seem to work fine with the auto about 4 months ago. Starting early on this problem before winter arrives. Thank you for your time.

I highly doubt the final drive ratio between the 4EAT and the GL 5MT are the same, that's why the car is binding very badly.

The 4EAT used a 3.70 ratio rear diff, and the GL (assuming non-turbo... D/R, correct?) is a 3.90 ratio. Big problems if you try to use 4WD with that mismatch.

yep mismatched front and rear final drive ratios.

OKay good to know. The GL 5 speed was non turbo. I figured as much because Just moving about 4 feet I could feel a lot of pressure building. whats the difficulty of a ring and pinion swap. 1-10, and whats the price I am looking at.

Far, FAR easier just to swap in a 3.90 rear diff. Standard diff on almost all Old Gen subes (Turbos excepted ). This should cure your bind and your concern about a leak.

Change the whole diff - you'll have to buy one anyway to get the ring and pinion, and it takes special tools to dissasmble them and change the gear set anyway..... yeah - get the whole diff.

 

GD