c85 8 speed tranny issues

[RollTideMike84 0]

OK not long ago I bought a 1981 c-85 and have begun to take it apart. I have removed the rear tyranny and want to know what the best way to secure the tranny for replacement of the hi/lo shift fork. I drained the fluid which looked like milk and the wheel hubs, shifter handles, and oil fill tube and dipstick. Upon removal of the dipstick I noticed it was chewed up like it got caught between the gears. It had two large gashes in it. Near the fluid level lines.

What could that be from?

Also I'm pretty mechanically inclined and want to do the work myself . How hard is it to change the shift fork?

The tranny seems to be leaking fluid but it looks like its leaking where the case splits in the center. Is there a gasket there or are they normally made with the liquid gasket stuff?

I will be buying the shift fork next week as well as a decal kit, paint, brake band, and shifter boots.

I am not fully taking the tractor apart and redoing it because it will be a worker. However it will be mostly redone and I want it ready to work. I plan on fixing it up to eventually resell it to buy a larger tractor. Its a great little pieceof American history but I need something bigger. Fixing the granny and brake band and new paint should allow me to get 800-1000 out of it with the wheel horse box blade and wheel horse brand discs along with it.

Both of those will be redone as well.

Anyways thanks for the views and of you all could enlighten me as to what I am getting into I would appreciate it.

Thanks fellas!

[Save Old Iron 1,566]

RTM,

best way to secure the trans is "dipstick" half down. Folks use various methods from stacked 2x4 cutoff pieces to milk crates to workmate benches to custom built jigs designed specifically for the purpose.

Once you split the trans case, you will find a similar arrangement to what you see below (maybe more rusty and certainly covered in putrid smelling oil / water emulsion).

Depending on which shifter fork you are intent on replacing, the speed forks and the HI / LO fork all are operated on the same principal of a captured ball bearing riding in a detented shifter shaft.

 

The speed shifters are captured by a spring / bar / ball arrangement as seen below.

Part numbers you may need are

http://i1228.photobucket.com/albums/ee458/SOI_University/speedshifterdetentsptnum_zps4234ad24.gif

The HI / LO fork is a similar arrangement with the fork retained on a detented bolt ( part numbers the same as for the speed shifters)

http://i1228.photobucket.com/albums/ee458/SOI_University/HILOshifterdetentptnum_tn_zpsacd24e11.jpg

Note - when removing the speed shifter forks, the spring loaded ball bearing detents are under considerable compression. The easiest way I have found of not having the ball bearing and spring fly out of the access hole (blue arrow in the lower left corner of the image below) is to cover the access hole with a strong magnet or place a magnetic retriever in the access hole.

 

 

 

 

When you have removed the main-shaft gearing (red arrow), raising the shifter fork (blue arrow) will allow the compressed spring / rod / ball bearing combo to expand out into the magnet and be retained within the trans housing. If the magnet or some form of barrier is omitted, the ball bearing and spring will most likely fly across your bench and possibly be lost or damaged in the flight.

[RollTideMike84 0]

Thanks man. I plan on splitting the case.tomorrow evening and start the.disassembly of the tranny. I have a feeling the shift fork is broken.

The tractor runs great in low gear but has no.hi gears.

[Save Old Iron 1,566]

Concentrate on the HI /LO shifter area.

p.s. you will need a trans housing gasket and may even want to consider replacing the axle seals while you have the axle / diff pulled out of the trans housing - all inexpensive items.

[RollTideMike84 0]

I priced the housing gasket. 4$

The Axle seals are leaking as well. I would love to replace those as well.

I will price them tomorrow. Along with the shifter boots. Broken boots is my guess as to why the gear oil looks like milk.

[Save Old Iron 1,566]

Broken shifter boots are the main reason. Some condensation will form inside the trans housing. Most condensation can be seen as rusty patches in the cast iron up under the shifter area.

Axle seals are a no brainer to replace. They can either be replaced with or without the axles in the housing. Some folks find it easier to replace them with the axles in the reassembled trans. Either way, the seals are easily damaged if run over any rough areas near the the woodruff key slot. Once over the key slot, they can be tapped into the trans housing with a short length of PVC pipe placed over the axle.

[Save Old Iron 1,566]

Regarding the marks on the dipstick, the dipstick does sit near the differential gearing and the differential support bearing. This picture shows the dipstick position with the differential removed.





I have to get that pic oriented better one of these days ......

 

 

Interesting how the oil level could be at 1/2 way down on the "safe zone" and be below the bearing

 

If the dipstick had or has any significant curvature, the tip may have become lodged into the gearing at some point during its lifetime. Then again, the dipstick may have been a damaged replacement or suffered damaged while it was outside the trans.