MTFCA Forum

JTT3 wrote: ↑

Mon Jul 14, 2025 11:00 pm

If I understood what your were trying to explain is that your triple gears are moving aft toward the drums & forward towards the flywheel on the triple gear pins. Is that correct? If so you may have some issues. The triple gears are only engaged in low & reverse however if not checked for correct tolerances (0.006-0.010) with new bushing you can have some slight movement but not much, if you used the old bushings and the flange face of the bushings are way below the minimum height you’ll have even more movement. Based on the information you gave that shouldn’t be the case. Other things to consider are loose pins, loose bushings in the triple gears because running tolerance were too tight & the bushings seized on the pins. In addition could be your clutch basket wasn’t properly spaced & locked down causing some drum float. If I’m not mistaken a clearance of 0.015-0.022 is within tolerance but if the clutch basket pin is not set correctly it can cause the drums to float a bit. In my opinion you should consider pulling the engine and check your transmission others may have a different opinion. Best John

J and M Machine wrote: ↑

Tue Jul 15, 2025 9:20 am

Sounds like you'll have to pull the engine. and take the flywheel off and see what happened to the transmission.

If you 've changed the oil like you mention then this shouldn't of happened unless it had no oil in it or rebuilder didn't do it correctly.

Greg sarky k wrote: ↑

Tue Jul 15, 2025 9:44 am

Sounds like the engine was rebuilt incorrectly. If you can see the triple gears moving then the bushings are bad. This sounds like you need to replace the triple gear pins and bushings because they wear out together. Could also be transmission problems you are not yet aware of.
Here’s my suggestion if you don’t want anymore headaches, I would pull the engine and take it to J and M Machine in Southboro Ma which is not that far from you..They are a true top tier machine shop,true pros.They have done 4 T engines for me and I have never had any issues..

What happened to you should not happen but unfortunately it does..I don’t know who did your engine but I do know of one unscrupulous builder in Massachusetts so yeah, it happens.

Good luck.

Dan McEachern wrote: ↑

Tue Jul 15, 2025 12:26 pm

viewtopic.php?f=2&t=6726&p=50746&hilit= ... ars#p50746

JTT3 wrote: ↑

Tue Jul 15, 2025 8:16 pm

So i reread your post carefully and wanted to ask several questions without jumping the shark on the builder until you know what you don’t know. You said you rebuilt the rear axle, did that include the modern pinion set up with a locking collar for the preload? Generally speaking, did you use a new pin for the universal & peen it over on both sides or the original pin same process. You said you have about 500 miles on the engine, paraphrased, how many of those miles were prior to doing the things over the winter months for the T you mentioned but after the rebuild? Did you have any issues during those miles prior to the rear axle being rebuilt? A u joint pin that is not tight & peened in the orifice can be slung out and “can” wedge against the driveshaft bell housing doing real damage to the transmission if in low, reverse & even catastrophic to the total engine assembly in high though not typically. I asked about the modern pinion bearing assembly. If you did use it, the Allen head bolt can sit very proud and cause a knock against the drive shaft housing but I haven’t witnessed or heard of that stalling an engine. As long as the engine didn’t receive any damage, minus the transmission damage, a rebuild on the problem parts will not be too costly though time consuming & aggravating. Wishing you the best of luck & a well working T post repair. Best John

JTT3 wrote: ↑

Wed Jul 16, 2025 11:09 am

Dan’s triple gear bearings are incredible, if you’ve decided to go that route buy his triple gear pins with the bearings. It’s really a must do unless you’re a glutton for punishment, ha!
Best John

big2bird wrote: ↑

Wed Jul 16, 2025 11:06 am

You will need a new flywheel and pins.
When the pins get loose, there is little you can do.

speedytinc wrote: ↑

Tue Jul 15, 2025 11:23 am

Before pulling the motor, have a competent & knowlegable T mechanic like J & M look & confirm the problem.
Its only fair to see if the original builder will warrant his work.

Thanks for the vote of confidence.
If we look at it ,you know what we're going to find
Problem with a Model T is it all has to be done, there is no 50%. The first 50% will affect second 50% and vice versa.
If they didn't do transmission, though did engine part all the dirt from flywheel and magnets will reintegrate with the engine part.
As seen in submitted picture of babbitted rear main bearing with debris stuck in it as babbitt does.
You'll see the bronze speckles .
second picture is dirty transmission. Just can't expect to get these clean by washing alone.


Money well worth doing it right rather than doing it twice.

RajoRacer wrote: ↑

Sat Jul 19, 2025 7:02 pm

First issue I see is that accessory 4th main bearing !

speedytinc wrote: ↑

Sat Jul 19, 2025 8:38 pm

If that bearing went out, & they do, could be a source of noise.

Jerry VanOoteghem wrote: ↑

Sun Jul 20, 2025 9:10 pm

Well, now we know the story. Sorry for you, but the good news is you caught it before more serious destruction occurred.

Erik Barrett wrote: ↑

Mon Jul 21, 2025 12:21 am

I have had to repair many transmissions with triple gear bushing failures. All of them were built with reproduction bushings and then set up too tight. Bushing seizes on the pin and either disintegrates or rips the pin out of the flywheel. Lang’s has Ford spec bushings but they are out of stock. The ultimate solution is Dan’s needle bearing gears. Second best is new triple gear pins and a set of original triple gears with Ford bushings. I have never seen a T transmission failure due to things being too loose. Always due to being too tight and inferior bushing quality.

Scott_Conger wrote: ↑

Mon Jul 21, 2025 10:28 am

"Running Fit" is a class of tolerance

Running or Sliding Fit can encompass any one of 9 sub-classes of fit from RC1 (Close Sliding Fit) all the way to RC9 (Loose Running Fit). FORD's ".002" Running Fit was likely an early equivalent to RC7 Free Running Fit or RC8 Loose Running Fit

Using the below calculator and entering ".677" for "nominal", "RC" for Running or Sliding Fit, and then either RC7 or RC8 and by going down to the "FIT" section, you will suddenly see that your final clearances are on a much looser side than you would imagine. Given that FORD's smooth broaches gave a nominal .004 clearance, and .005" clearance was at max limit, I'd imagine that FORD's class of fit would be defined today, by ANSI B4.1, as the upper limit of a RC7 Free Running Fit that is defined as ".0045" at it's upper limit.

FORD's ".002" was never a tolerance or final clearance fit - it was part of defining what class the "Running Fit" was.

https://amesweb.info/fits-tolerances/an ... lator.aspx

Glenn Chaffin had it right, years ago. I disagree with some of his explanation of how he applied the spec, but he was on the right track, and in fact his conclusion(s) and build philosophy were correct both in theory and practice. All the naysayers and folks who gave him no end of grief would have had even more time to disagree with him if they were not so busy re-rebuilding their transmissions.