GMC 4104 Drive shaft installation

Bob & Tracey · May 08, 2016, 12:00:47 PM

luvrbus,

I thought we had a good plan, please share your concerns.

luvrbus · May 08, 2016, 12:14:29 PM

They never go back to the same lash for me, your luck maybe better though but all the vibration I bet the contact between the ring gear and pinion has changed

Bob & Tracey · May 08, 2016, 12:25:39 PM

Thanks, I guess we need to rethink this...

azdieselman · May 08, 2016, 12:34:23 PM

The backlash is set by shims between the differential housing and the pinion cage? If we reassemble everything the way it was it should be ok? We are at Eagle Nest in Nashville.

Those shims are for setting pinion depth. They will affect backlash, But that is set by moving the ring gear toward or away from the pinion.

There may be some numbers etched into the end of the pinion, That is the deviation from "standard". They assist with the depth set shim selection. Just reuse yours or replace them with the same thickness.

Backlash is set with the pinion held firm and the ring gear "rocked" to find the lash/freeplay.

It may be OK still, But if it clunks or whines, You're going back in again.

Verify that the splines are not worn, A loose yoke can tear them up.
You can replace the yoke if the fit is a little loose.

Bob & Tracey · May 08, 2016, 12:57:41 PM

Thank you azdieselman, luvrbus, Tom and eagle

I am going to share what we have discussed here with the guys in the shop and hopefully we get it right.

Bob

dvrasor · May 08, 2016, 03:31:17 PM

I agree with Cliff. I would not feel comfortable unless I pulled the pumpkin.
A lot of damage could have happened when pinion bearings lost their preload.
Sounds like the "mechanic" dropped the ball big time. I rebuilt mine about 8
years ago myself. It is not a small time job.

Dave Rasor
4104-2375

mcmusic · May 17, 2016, 11:08:03 AM

I saw your question about a driveshaft on 4104 - I assume that this has been a conversion to a V8 and a 730 tranny. In order for this to work in a 4104 the housing has to be out of a 4106 or 4905, anything that had a 730 in it. If you don't change the rear end you will have some really hideous driveshaft angles. In other words, the 730 transmission has a completely different angle from a 4104 transmission. In order to do it correctly you have to change the housing which moves the center section to the left of the bus and allows the driveshaft to have minimal angles. If this hasn't been done you are running really bad angles and you will never keep a driveshaft in it. I have not looked up the exact changes that will correct his and there is probably a better source than me. My 04 has been around too long and I've forgotten most of what I ever knew about it. Hope this helps you get going in the right direction. Thank you.

chessie4905 · May 17, 2016, 12:03:15 PM

Since my 4905 sits over my pit, I went out and measured. First a 4106, 07, 08, and 4903,05, have their differential mounted to the right of the rear axle housing,(looking from rear of coach) about as far right as it will go without hitting suspension beam. The distance from the right side of the differential mounting flange to the back side of the brake drum is about 9 1/2 inches with its 10 inch brakes. Probably would be 11 1/2 with 8 inch brakes on a 4106,07, and 08, and if it still had 4104- 7 inch brakes, it would be 12 1/2. Btw, what is the ol of your driveshaft? Mine is 22 1/2 flange to flange. (V730) I think that the differential on the 4104 is mounted to the left of center of housing. The drive shaft on our 4104 was about 4 feet long, from memory.

Bob & Tracey · May 17, 2016, 05:04:29 PM

Thanks for the help,

The housing is 4104 but the differential is out of a 4106. This conversion was done in the 80's and has not had driveshaft problems. This repair is a result of the propeller shaft/pinion nut backing off and allowing the shaft to exit.

RJ · May 17, 2016, 06:14:51 PM

Quote from: Bob & Tracey on May 17, 2016, 05:04:29 PM
The housing is 4104 but the differential is out of a 4106.

Bob -

Which side of the coach centerline does the differential housing/pumpkin sit, when viewing from the rear of the coach? Street or curb?

FWIW & HTH. . .

Bob & Tracey · May 21, 2016, 07:32:42 PM

RJ,

Without measuring it looks like it is on the street side.

uncle ned · May 23, 2016, 12:52:48 PM

RJ in all my doing around 04's it have came to the belief that the only difference in the 04 and the 06 is the pumpkin.

I helped Jara Smith put 2 6v92'S and 730's IN 04'S and all he changed was the pumpkin.
he had to do some cutting in side of the axle so the pumpkin would fit.

I would bet that my 04 which he installed the 6v92 in about 12 years or more ago.
Had engine problems but never a drive shaft or axle problem.

Hard Headed Ken can give more info than any one than I know.

uncle ned