Death of a transmission

[twr]

Well, I decided to open up the core transmission a got after I sold one of my spares to a local club member.

The suspect. Transmission out of a '92 that was driven hard and had a recent clutch job. The input shaft was locked up, the transmission shifted fine and the diff. spun fine.

First thing I spotted and figured into the failure.

Time to drain the fluid? Uh, fluid?

Time to loosen the bolts, except these three as they are already loose.

Okay, what's wrong with these pictures?

Looks like some serious heating happened here.

5th gear shaft

Not much on the case magnet.

Upon closer examination, it looks to me as the transmission was not filled after the clutch job or the fluid leaked out. There is no rtv blockage to be seen anywhere. The discoloration on the case (inside and out) and what was left of the fluid, 5th gear shaft and the input shaft bearing leads to me to believe it was run dry.

My question is, since it seems all the bearings will be shot, should I bother rebuilding this transmission, or just keep it as a spare parts. I still have one good working spare transmission.

 

[TYSHO]

Have you tried pulling the gears off the mainshaft? If not, I don't think you will be able to!

 

[shoteen95]

that bearing is hot...

get it? hot? :laugh_ti:

...nevermind.

What a shame, a decent transmission killed by carelessness...

 

[Bizzy]

Terry, most of the parts should be reusable. If you question the synchros just disassemble them, give them a good cleaning and exam before you reuse them. I'd replace all the bearings for obvious reasons. That input shaft may have some damage under where that bearing sits. Other than those things I think you'll be good to go. I'd keep it as a spare.

Edit: The outer race for the input shaft has what looks like a chunk taken out of it. If any of the rollers are missing out of the bearing make sure you double check all the gears & shafts for chunks taken out of them.

 

[twr]

Bizzy,

Thanks, I'll get a hold of Josh regarding the bearings. I may just finish up my inspection on this trans, and bag all the parts for the time being. I suspect when my trans lets go, it will be 3rd gear on the input shaft, so having spare parts won't be a bad idea.

Terry

 

[rangerj]

twr,

Just sum thoughts:

Keep in mind that heat tends to distort things. You may want to check parts you intend to use with a straight edge and/or a pair of calipers. The bearings and races may not be the only things buggered up. Further, heat also tempers metal. The gears and shafts may be straight enough, but brittle as glass.

 

[twr]

twr,

Just sum thoughts:

Keep in mind that heat tends to distort things. You may want to check parts you intend to use with a straight edge and/or a pair of calipers. The bearings and races may not be the only things buggered up. Further, heat also tempers metal. The gears and shafts may be straight enough, but brittle as glass.

Good point, I'll have to take a closer look. It really looked like the bearings took the brunt of it, but I'll eyeball the shafts a little closer. Worse case is this trans will be for parts (synchros, blocking rings and the case)

 

[TYSHO]

Worse case is this trans will be for parts (synchros, blocking rings and the case)

That's if you can remove the gears!

Usually, when you run the tranny dry for a long time, the splines on the mainshaft will flatten. The same splines are the ones that the synchro slides up and down to remove and install, plus hold it in place. If indeed the splines are flattened, the gears will be stuck, especially 2nd and 3rd. If it was ran for very little, you might be able to remove 4th gear no problem and then the 3/4 synchro will slide right up and out, but forget the rest.

 

[jelloslug]

I'm with TYSHO: Chances are you will have a hard time getting the synchros and gears off those shafts. I had the pleasure (or misfortune) to tear down a trashed MTX-4 from a friends parts car (slightly blown diff and all the oil leaked out causing MASSIVE internal friction damage). We broke teeth off of every gear trying to press off the gears (they are suppose to be slip fits).

 

[twr]

Well,

I was able to disassemble the main shaft. RTV had plugged up the passages in it. So it's looking like this lead to the tranny failure. But I'm still suprised at the lack of fluid in the tranny when I opened it up. Maybe a combination of the 2 finally killed it. The owner has never had tranny work done on the car in the time he's owned it and he droves it very hard. Not to mention, it's a little ironic that it failed shortly after the clutch was replaced. I have more pictures to post, but comcrap was on the fritz last night... again,