1991 2,3L, 5 speed manual, 2 wheel drive, standard cab.

I had an issue with my transmission and ended up having it rebuilt. When back in the truck, I found it to be leaking fluid, leaving a small puddle any time it was stopped and the bottom of the transmission dripping fluid. A little searching here led me to the discussion of the "rubber plugs" issue - something I was completely unaware of. Although they look to be new, I will be replacing them, with the Dorman plugs, just to be sure.

Which brings me to my question - when I pulled the drive shaft to get better clearance/angle, (no mention of the "access plate" in my manual or any of the posts I saw prior to starting this effort) I got probably 1/2 to 2/3 of a cup of transmission fluid from the output shaft of the transmission - where the splines of the drive shaft engage. This doesn't seem right to me - all of the transmission fluid should be inside of the transmission housing? Bad/improperly installed rear seal? Any other ideas?

Jeff Rees

 

There are gears in the rear section of the trans, they have to be lubed, also the drive shaft yoke has to be lubed, or the bushing won't last very long. As long as the seal you can see at the end of the tail housing isn't leaking, you're good to go. As for the other leak you mentioned, is it coming from the three plugs, or leaking around the tail housing where it mates the main case?

 

It appeared to be leaking form the "top" of the transmission. When I got access to the top, where the previously unknown to me, infamous three rubber plugs are, there was evidence of transmission fluid there. I am in the process of replacing the rubber plugs with the Dorman plugs - wish I'd seen the information while I had the tranny out of the truck.

That said, the presence of and the quantity when I pulled the drive shaft really surprised me. If this is normal, so be it - just NOT what I was expecting.

Thanks for the input.

 

If you just had it rebuilt, the shop that did the work should be the ones fixing the plugs on the top of the transmission. The plugs, when they fail, turn to 'crumbles' of rubber, and will not seal at all. The lube will be thrown up against the floorpan. At least I think that is the case from all I've read of the description.
The lube will get thrown around inside the transmission, and will get thrown at one side of the case more than the other due to rotation. There will be in a lot of transmissions, a 'shelf' or what appears to be a ledge along one side that will use gravity to channel the lube to places that are not getting splashed, such as the rear bearing, and perhaps the OD gears and associated bearings, which are in a 'add-on' case in many models, rearward of the main case. The lube all falls to the bottom, and seeks a common level within the case. There is a passage that connects the OD case and the main case to allow leveling of the lube. The output shaft gets fluid dribbled onto it from the OD gearset, and some will stick and make its way back to the output shaft bushing in the tailhousing. A lot of output shafts will have a 'slinger' that will 'catch' the migrating lube, and cause it to spin off the shaft and get flung to the inside of the tailhousing. That limits the amount of lube reaching the bushing and the seal. A slinger is any sort of interruption of the surface that has a 'rise' or raised level above the output shaft diameter. The lube will move 'out' onto the high spot, and will not climb back down to travel further down the shaft. It will be flung off by centrifugal force, fall down the wall and travel back to the sump area.
When you tilted the transmission down, you allowed that little bit of lube in the 'sump' to wander down to the tailshaft bushing, and out onto the ground with the drive shaft removed, opening the sealing area wide. There will always be some lube in the tailhousing until you run it low enough via the rubber plugs leaking it out to rustproof your truck, or seepage past the shift linkage or the tailhousing seal or the input shaft seal. I have some migrating up the speedometer cable adapter and cable on my old truck. It has been 'wet' with 85W90 since it was new.
tom

 

And I thank you for the description/explanation - it makes sense that there would be some fluid there - I guess it was just the quantity that surprised me - as I said, maybe 1/2 to 2/3 of a cup - made a large puddle! The truck was jacked up in the rear end for clearance and actually had a slightly nose down attitude when this occurred, so would have expected the "drainage" to be in the other direction.

Based on the input, I'm guessing this is normal and my leaks are elsewhere. The infamous rubber plugs look to be in good condition - I am assuming they were replaced by the shop because they are definitely not 23+ years old in appearance!!

Jeff Rees

 

You said it appears to be leaking some from the Top of the tranny, so that makes me want to ask if the shifter gasket/seal is installed correctly & intact????
I agree the rubber plugs belong on your suspect list & I'd add the fill plug too.
Let us know what you find.

 

On this go-round, I've found that the top shifter arm gasket/seal is a bit beat up - and could be a source of the fluid. It would appear that it was NOT replaced as a part of the rebuild - and I have on on order to install and hopefully stop this leak.

I haven't really been able to isolate THE cause, but have definitely identified and am correcting several suspects!

Thanks for all of the ideas and input - it helps!

Jeff Rees

 

OK, let us know when you do find the culprit & as suggested by tomw this was the rebuild shops responsibility. So when you do finally get things put right, save the faulty part/s & take them along to have a serious face to face talk with the shop Owner!!!!
Take plenty of photos to document the leak spot/s & what the part/s looked like before removal/replacement.