Rebuilt Trans + Torque Tube, Groaning / Grinding On Deceleration

[left.covst]

Hello all!

Long time reader, first time poster.

Recently performed some sealing and light rebuilding on my '40 side-loader and torque tube combination under my '34 pickup. A failed throwout bearing had me in there, so I took the time to fix all leaks and install an oil baffle from Bruce for the rear end to end my rear end > torque tube > transmission leak.

I replaced - input shaft bearing, snap rings, throwout bearing, countershaft thrush washers, a bent oil slinger, and all seals. Thoroughly cleaned and re-assembled the transmission. Also replaced the front driveshaft seal and bearing race, cleaned and greased the original torque tube roller bearing.

I also cleaned the torque tube and found my center bearing in visibly good shape, and re-greased it.

At the rear end I found the double nut for the pinion loose, and cranked it down a bit, without much thought to the pre-load / tightness at the time. Installed the baffle at the rear of the torque tube, and re-assembled everything.

Greased the u-joint well and thoroughly with cornhead grease until it made it to the front of the speedo gear.

All went well, and it all went together nicely and sealed up tight. Shifting is perfect, and it was nice and quiet for about 20 miles.

Unfortunately it has since developed a loud groaning / howling noise when in gear and coasting (engine braking). This continues until about 15-10 mph and then quiets down.

Pressing in the clutch will stop the noise, as well as pushing the trans out of gear.

It occurs only when coasting, and disappears as soon as the throttle is applied enough to positively drive the gears + rear end.

In reverse gear the groaning / grinding noise is not present.

I have three suspicious and would appreciate any input before I tear back into things:

1. Pinion nut was too tight - Causing bearing noise due to the pinion bearing.

2. Roller bearing in the torque tube inadequately lubed - Cornhead grease flowed to the top of the speedo gear opening, but I did not continue to pump it into the roller bearing area. Though I did pre-grease that section.

3. The original transmission roller bearing (either on the counter shaft or input-mainshaft ones) which were cleaned, greased, and reinstalled (though perhaps not in their original positions) could have failed or are failing OR the replacement thrust bearings on the countershaft are making noise.

Appreciate anyone's thoughts!

[Ken/Alabama]

Sounds like too much backlash in the rear end.

[petehoovie]

Very Nice '34 Pickup...

[deuce_roadster]

By tightening the 2 nuts on the pinion you moved where the gears touch each other and most likely increased the backlash. I would guess the worn area on the pinion is meshing with a differently worn area of the ring gear. Probably should redo the whole thing with new gears and bearings and set it up correctly.
Nice truck.

[ford38v8]

What Deuce Roadster said, and if you've driven it like that for a while more than just around the block, you'll find shavings in the differential oil. By the way, that double nut... Didn't it have a locking fold-over washer?

[left.covst]

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Thank you all for the feedback! I think Deuce likely nailed it.

Alan - Definitely drove it more than needed to toast it if there was a mesh issue. I'll try to do some additional diag with it running up on stands to isolate the noise and ensure it's in the rear end and not transmission area. I'll probably drop the diff oil as a final check before I split the assembly again, hopefully i'll find a smoking gun.

Might be an excuse to put a quick change center section in.

The pair of nuts did have a locking fold over tab, locking the two nuts together and neither of them tight, haha.

Alan - I see you're in the Bay as well, San Jose here!

[ford38v8]

Left Covst, yes, I'm here in Livermore, not really that far Left. As your locking tabs were folded over, but the nuts were loose, the likely cause of failure would have to be that a new pinion bearing had been installed short of full seating. That bearing is a press fit, and to do it without a press would require freezing the bearing and heating the banjo. Without a visual confirmation of full seating possible, this method and the use of a BFH is the only way I would do it. It takes a while to get a jig set up, but then just one big whap with the hammer does the job. I could have taken it down to Campbell, but was stubborn about doing it all at home. Bill is good about allowing V8ers to use his press.

[left.covst]

Nice Alan! I have a friend in the Walnut Creek area, I'm sure we'll cross paths before long.

Understood on the install. I am leaning towards a quick change rear end center section (Winters SR3620) as the ring and pinion do seem toast. Luckily I have a friend with a press for the carrier bearings should I go that route.

I got the car up on the stands and ran it today - Two videos attached of the truck running and the oil out of the rear end, I think it's safe to say I found the source of the noise.

https://share.icloud.com/photos/052B...wFkURN97d_HnPg

https://share.icloud.com/photos/04eO...23H6sLy2YPIUpg

[deuce_roadster]

After looking at all the pictures, the one of the transmission doesn't look right to me. You can see the brass synchro ring on the main drive gear but with the synchro sleeve in the second gear position it looks to me like there is way too much space between the 3rd gear brass and the synchro, more than the entire notch looks exposed. Maybe it is just the camera angle. Been a while since I put one together but maybe a trans expert will chime in.

[left.covst]

Originally Posted by deuce_roadster

After looking at all the pictures, the one of the transmission doesn't look right to me. You can see the brass synchro ring on the main drive gear but with the synchro sleeve in the second gear position it looks to me like there is way too much space between the 3rd gear brass and the synchro, more than the entire notch looks exposed. Maybe it is just the camera angle. Been a while since I put one together but maybe a trans expert will chime in.

Deuce - You're totally right, that was on disassembly and the input shaft had already slid forward out of the case, on re-assembly it was correct as seen here (attached).

[V8COOPMAN]

Originally Posted by left.covst

Might be an excuse to put a quick change center section in.

Be aware that a quickie will not live happily with the STOCK rear crossmember, without a bunch of crossmember surgery.

The noise you're hearing upon deceleration is what you can expect ANY TIME a pinion bearing is compromised in any way.

Coop

.

[left.covst]

Originally Posted by V8COOPMAN

Be aware that a quickie will not live happily with the STOCK rear crossmember, without a bunch of crossmember surgery.

The noise you're hearing upon deceleration is what you can expect ANY TIME a pinion bearing is compromised in any way.

Coop

.

Thanks for pointing that out Coop - Definitely saved me a ton of grief. Looks like a stock rebuild is in the cards in that case.

[bbrocksr]

Originally Posted by left.covst

Thanks for pointing that out Coop - Definitely saved me a ton of grief. Looks like a stock rebuild is in the cards in that case.

Coop is right , Pinion bearings. Anytime you have howl or growling noise on deceleration you can bet its pinion bearings,
Bill

[left.covst]

Originally Posted by bbrocksr

Coop is right , Pinion bearings. Anytime you have howl or growling noise on deceleration you can bet its pinion bearings,
Bill

Thanks Bill, appreciate everyone's help in confirming my suspicions. The noise was pretty apparent, but since I had so much apart I wanted to be sure it wasn't something else leading me astray.

Starting to make a list from the Van Pelt catalog and plan on some tools like a dial indicating torque wrench, seal driver, and hub puller for the job.

This tool kit from Mac's seems to be the right fit for my needs to pull the pinion bearings and double race themselves.

I also see suggestions that the Mitchell puller may be the preferable option.

Open to any other pointers or tools I should be thinking of outside of a press.

[ford38v8]

Originally Posted by left.covst

Thanks Bill, appreciate everyone's help in confirming my suspicions. The noise was pretty apparent, but since I had so much apart I wanted to be sure it wasn't something else leading me astray.

Starting to make a list from the Van Pelt catalog and plan on some tools like a dial indicating torque wrench, seal driver, and hub puller for the job.

This tool kit from Mac's seems to be the right fit for my needs to pull the pinion bearings and double race themselves.

I also see suggestions that the Mitchell puller may be the preferable option.

Open to any other pointers or tools I should be thinking of outside of a press.

One tool most essential to Early Ford mechanics is a fully stocked beer refrigerator.

[left.covst]

Well, it would certainly appear the nuts moved since I saw them last.

[cas3]

I always like to use a new lock washer there as the inside tab that locks to the shaft can break without you knowing, most likely what happened here.

[left.covst]

Originally Posted by cas3

I always like to use a new lock washer there as the inside tab that locks to the shaft can break without you knowing, most likely what happened here.

Unfortunately the boogered nuts and ring are the result of a previous individual, but it'll get fixed right!

[ford38v8]

It’s been a while, but I seem to remember that those locknuts come as part of the order along with the bearings for exactly that reason. They seem so inadequate for the important task they perform.

[left.covst]

Originally Posted by ford38v8

It’s been a while, but I seem to remember that those locknuts come as part of the order along with the bearings for exactly that reason. They seem so inadequate for the important task they perform.

I ordered fresh lock nuts, and an NOS lock washer. I had heard issues about the tangs on repro's catching the edge of the torque tube which may have been what happened here. Either way it seems to have been re-used too many times and bent all out of shape.

In either case I'll ensure they're firmly locked in place, not just to each other. I also ordered a dial Torqometer so I'll be able to correctly set the 15-20 inch pounds, and 1-7/8" wrenches to get the nuts properly done up. I added a Mac's Fab pinion puller as well to get that bearing race out.