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M5/M6 Question


James_Douglas

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I have a friend with a '46 Chrysler and his M5 Transmission is jumping out of gear and going into free wheeling state under high load - high RPM conditions in 2nd or 4th gear.

Once you back off the throttle is jumps into 1st or 3rd, depending if you are in low or high range.

All the usual suspects look fine and it work normally 99% of the time. It is just under high load, saying like going up a hill and high with RPM.

I have looked over all the books and service tips on the Imperial Site and I cannot find anything referencing this particular issue.

Anyone have a clue ?

James

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More than likely the input shaft and blocker ring and sleeve teeth are worn. Under torque load the direct sleeve could possibly be forced forced back off the input shaft teeth- causing it to kick back into low range. Here are pics of worn and new parts mentioned. These are very hard to find parts and $$$. Michells has the blocker ring and sleeve pkg. I'm not saying this is the problem but am pretty darn sure of it. Electrical and fluid/idle speed must all be correct 1st.

Bob

Edited by Dodgeb4ya
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Bob,

When it pops out, it goes into free wheel...then when you let up off the throttle it drops back into 1st or 3rd as the case may be.

I figured that blocker ring and associated parts were the issue...I wanted to ask around though before I tell my friend.

He just paid a lot for the '46 T&C Convertible and I hate for him to have to pay me to rebuild a trans for him.

I happen to have an extra core I am not using and so I will tear it apart and see what it looks like.

Anything else you can think of on the inside that would cause the same issues?

Thanks, James

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Hey James, I haven't got a clue on the M5, but my 49 with the M5 was rebuilt in CA. Here's their name and # if you want to run it past them.

Macy Automotive

Concord, CA 925-689-3200

For rough idea of prices:

$1200 for rebuilt tranny (fluid coupler, clutch set, standard bearing seal kit, Plate bolts, Brg Assembly)

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Hey James, I haven't got a clue on the M5, but my 49 with the M5 was rebuilt in CA. Here's their name and # if you want to run it past them.

Macy Automotive

Concord, CA 925-689-3200

For rough idea of prices:

$1200 for rebuilt tranny (fluid coupler, clutch set, standard bearing seal kit, Plate bolts, Brg Assembly)

Wow! In the "Bay Area" and even has a BART station. That makes it almost as convenient for James as someplace in "the City".

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Bob,

When it pops out, it goes into free wheel...then when you let up off the throttle it drops back into 1st or 3rd as the case may be.

I figured that blocker ring and associated parts were the issue...I wanted to ask around though before I tell my friend.

He just paid a lot for the '46 T&C Convertible and I hate for him to have to pay me to rebuild a trans for him.

I happen to have an extra core I am not using and so I will tear it apart and see what it looks like.

Anything else you can think of on the inside that would cause the same issues?

Thanks, James

The free wheeling cam and roller assembly in the countershaft is another problem area-not nearly as common as the input shaft to direct speed sleeve issue. Sounds like the trans needs to come out and be taken apart and thoroughly inspected. I think the input shaft area is what I'd check into 1st. I recently rebuilt a M-5 on a 47 T&C convert with the exact same issue. Put in a new input shaft and a new direct speed blocker ring kit and it shifts totally quiet -smooth and quick.

Bob

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Adam,

Thanks for the info...but $1200 for all that stuff is WAY to cheep. A properly rebuilt fluid coupling starts at $400 alone and only one place in the US still has the tools to properly cut it open.

The rest of the parts for an M5/6 that wear will run into $500-$1000 range. Then there is the labor.

Sounds more like they cleaned it and did a repair, certainly not a rebuilt unit.

Best, James

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Bob,

I think you may be correct. When the car was inspected prior to purchase it has the same problem, but more pronounced. The seller had someone "repair" it prior to shipment from MN to CA.

They told the owner that it was the free wheeling cam. I suspect that is AND the input shaft was causing problems and now the input shaft needs replacing.

Thanks for the insight.

James

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Bob,

I think you may be correct. When the car was inspected prior to purchase it has the same problem, but more pronounced. The seller had someone "repair" it prior to shipment from MN to CA.

They told the owner that it was the free wheeling cam. I suspect that is AND the input shaft was causing problems and now the input shaft needs replacing.

Thanks for the insight.

James

Hi James, someone I know on PWHM 46 to 48 Chrysler's stated this,

Re: Fluid Drive Transmission woes

Unfortunately, a worn input shaft can cause that slipping out of gear as well. I had it once.

Just for info - I refilled my M6 with SAE 16ish (mix of 1 liter10 and rest 20)

Now can't even hear the "thunk" when it shifts.

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Hi James, someone I know on PWHM 46 to 48 Chrysler's stated this,

Re: Fluid Drive Transmission woes

Unfortunately, a worn input shaft can cause that slipping out of gear as well. I had it once.

Just for info - I refilled my M6 with SAE 16ish (mix of 1 liter10 and rest 20)

Now can't even hear the "thunk" when it shifts.

Thicker oil will sometimes, because being thicker causes oil pressure to increase to help keep a worn input shaft and blocker ring assembly to keep locked up in high range. It will pop out sooner or later till properly inspected and repaired. I have run 10/30 in old clunkermatic M5/6 transmissions too- quick upshifts and slooow downshifts.

Bob

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