6 Speed Leak Fixed!

[ISB RAMBO]

From the day I picked up my truck with 6 miles on it, the front of the transmission had a little oil on it. The leak was so small that it took 6 months for the first drop to hit the floor. Eventually it got worse and what I'd see is a silver dollar sized spot on the garage floor and then no more leaking for 4 or 5 days. This drove me crazy since it was not consistent. Brought it to the dealer and they replaced the front shaft seal. No leak for a few days after, then the silver dollar sized leak overnight again. Back to the dealer and they put in some dye that would show up under black light.

Brought the truck back to the dealer and they found the problem. This is interesting because the 6 speed transmission is different than other manual transmissions. What the 6 speed does not have is a front. The back of the bell housing is the front of the tranmission. I was totally confused when the mechanic first told me this, but when the bell housing is removed from the transmission, you are looking into the transmission and are seeing the gears. Anyway they put a sealant between the transmission and bell housing and the leak is gone. Both the mechanic and I learned something. Happy at last!! (Hate to think what this cost DC).

Stan

 

[wyosteve]

Thanks for the info. I've been having the same problem and couldn't figure out how to fix it. That info will help.

 

[klenger]

Interesting:



What hold the front bearing in place? I assume there is a front bearing. What does this mean to people who want to upgrade from the 5 speed to the 6 speed? New clutch and housing too?

 

[RustyJC]

Originally posted by klenger

Interesting:



What hold the front bearing in place? I assume there is a front bearing.

Ken,



Yeah, the only way I could see this working is if the front bearings on the mainshaft and countershaft(s) fit into bores in the rear face of the bellhousing. Even then, how would you ever locate the shafts precisely enough to hold tolerances on the gear meshes given the "slop" in the bolt-up of the transmission case to the bellhousing, unless that's a doweled fit... Man, would I hate to try to hold those tolerances in production!



Of course, I'm not curious enough to crawl under the truck tonight and drop the transmission!



Rusty

 

[DRR-24V]

Gotta See It First !

ISBRAMBO,

I am not doubting what you were told, I would just have to see it to believe it. The countershafts and mainshaft would have to have support from the bellhousing and I just don't think this would be the way to go. I am NOT FLAMING, I just hope you got some bad info.

 

[ISB RAMBO]

I know, it is hard to believe. I am not a mechanic so let me give you what I can see.

The mating surface of my bell housing and transmission now has a read sealant that was not there before. The bell housing has 10 bolts to the transmission according to page 21-110 of the service manual (no big deal). Bolted (12 bolts) to the inside rear of the bell housing is the input shaft retainer, pg. 21-121. What I can't see from the diagram is whether or not there is a bearing inside this input shaft retainer. One other thing the mechanic told me was that if the front shaft was leaking, oil would be in the bell housing, this was not the case with my leak - it was external only. Need a 5600 transmission expert to answer any detailed questions.

The mechanics explanation sure makes sense after they originally replaced the front shaft seal and the oil leak remained. Anyway, the bottom of my transmission is, for the first time, dry as a bone.

Stan

 

[Dave Fritz]

From MasterTech issue No. 11 November 1998



At the front of the transmission, the all-aluminum clutch housing (Fig 7) mates to the engine block and includes the front bearing bulkhead. The clutch housing is integral to the gearbox, and cannot be separated from the transmission while in the vehicle. Note: after the transmission has been removed from the truck, the bellhousing bolts can be removed, and the bellhousing can be separated from the front of the transmission - Dave



#ad




Shims for the mainshaft are installed into the input shaft retainer, while countershaft shims are installed between the bearing race and space (Fig 24). Note that the bearing bulkhead is visible in fig 7. In Fig 24 you can see how the bulkhead is removed to shim the transmission input and counter shafts. The rear of the bellhousing is also the front of the transmission, and the bulkhead supports the input shaft seal- Dave

#ad




Did that help?

 

[RustyJC]

Originally posted by Dave Fritz

Did that help?

Dave,



Yep, a picture really IS worth a thousand words!



Rusty

 

[DRR-24V]

Thanks To SuperDave

I knew you or Peter would know. If I can understand it now, anybody can.

 

[wyosteve]

Dave, YOU DA MAN!!

 

[klenger]

Well, I'll be dipped...



Thanks Dave

 

[ISB RAMBO]

Thanks Dave! My words can't match your pictures.