98 4r70w in the trans shop-loose extension housing leaked out my fluid :mad:

[Mbrooks420]

Well on Friday my trans started to shift in and out of OD and drive erratically. The truck started vibrating a few days before. I decided I'd take it in to my local trans shop and have it looked at. They called and said my t case came loose from my extension housing and my trans was low on fluid. On the way to the shop i had a delayed/slippy reverse, so I assume the fluid was quite low. As of now they think the trans might very well be fine. Tomorrow they plan to change the t case fluid, reseal it, and run it without the front d shaft to see if the vibration is still there. They seem to think it's a joint on the front shaft. I'm hoping that
1. My t case isn't damaged due to improperly matched shaft and gears
2. I don't have to pay to have the t case put back on correctly, to only
3. Also have to rebuild the trans due to driving with low fluid.

If it needs rebuilt what are the updates the tranny really needs? Get rid of the scarf seals for the sized GM seals? My trans shop is pretty good about updated parts and whatnot, though I doubt they know about the sized GM seal kit.

 

[Mbrooks420]

Well, maybe I got lucky. They put a new gasket on the t case, changed the fluid in the t case, and tranny with a new filter for $400. I suppose i could have done it but the service guy said 3 of the bolts broke off which probably would have ruined my weekend. It seems to shift and especially downshift a little better. I wonder if maybe the fluid was a little low for awhile. The old fluid looked very well for 130k. The fluid may have been changed before I got it at 63k. It seemed well taken care of. Considering the plowing, and general hard life it has lived since I have owned it I think it has stood up surprisingly well.

 

[Glacier991]

I am doubting that low fluid has caused any lasting concerns... keep that fluid clean, cool, and use Merc V and you should be fine. The 4R70W is a tough tranny. There are a number of upgrades, and many of them I discuss in the 4R70W Rebuild Diary. The solid seals on the output shaft where it enters the direct drum is one of the more important ones, but by no means the only one.