Need some help all

[jclimie]

Hey all I have a 1971 c10 short bed with a 454bb out of a 1993 454ss and just had the transmission rebuilt and drove it for the first time today. We put it on the rack to make sure there was no leaks and the torque converter and flexplate had a wobble to it. Wondering if flexplate bent? I checked for cracks and saw none. Or need to shim torque converter back a little. Any advice or help would be great.

Thanks
JC

[TBONE1964]

Originally Posted by jclimie

Hey all I have a 1971 c10 short bed with a 454bb out of a 1993 454ss and just had the transmission rebuilt and drove it for the first time today. We put it on the rack to make sure there was no leaks and the torque converter and flexplate had a wobble to it. Wondering if flexplate bent? I checked for cracks and saw none. Or need to shim torque converter back a little. Any advice or help would be great.

Thanks
JC

Hey JC, If your torque converter has a wobble then your front pump bushings may be wore out in the front pump of the trans. If this is the problem, you will have a front pump seal leak in a matter of time. I would think that the trans shop would have replaced the bushings if not the entire front pump. It is also possible that the snout on the converter is bent. That would most likely happen if it was dropped. I have seen flexplates with a small amount of runout but nothing that caused problems. Try unbolting the flex plate from the converter and see if you can rock the converter back and forth. It should not rock. Also while it is unbolted, turn the converter by hand and see if you can notice the wobble that way. Good Luck.

[jclimie]

trans was totally rebuilt and new torque converter. I had concerns that the gap between the converter and flexplate was too big but everyone said it was ok. With the converter all the way in or pulled out 1/8 inch no wobble. The gap between the converter and flexplate is at least 1/4 or greater.

[GASoline71]

Maybe i'm reading this wrong. But there should be no gap between the TC and the flexplate when the TC is bolted to it. The TC should always slide out a tad, and the mounts should bolt up flush to the Flexplate.

Gary

[jclimie]

Correct but I think the spec is that the torque converter should only slide out less than a 1/4 inch. mine comes out probably over a 1/4 there is no gap when its bolted up but I just feel that its coming out too far. I bought a shim kit and was going to shim it .120 to get the converter in a little more, but everyone said no its ok.

[GASoline71]

I'd bolt it up and run it. If it's an original trans to the 454 with a stock converter. No sweat...

Gary

[TBONE1964]

Originally Posted by jclimie

Correct but I think the spec is that the torque converter should only slide out less than a 1/4 inch. mine comes out probably over a 1/4 there is no gap when its bolted up but I just feel that its coming out too far. I bought a shim kit and was going to shim it .120 to get the converter in a little more, but everyone said no its ok.

Be careful with this. The gap is there for a reason. With heat, the TC will grow a little(expand). It is not noticeable but it does. If there is not enough gap, the TC will push the crank shaft forward and wipe out the thrust bearing in the engine. Also it will wear out the front pump in the transmission. .120 is just shy of an 1/8 inch. make sure you do this according to the specs. I would hate to see your newly rebuilt trans full of metal shavings or worse.

[turbosix]

If I understanding the problem correctly, it sounds like the converter is not going into the end of the crankshaft like it should. When this happens there will be a gap between the flexplate and converter pads and when it's tightened up it will distort the flexplate.

[jjzepplin]

I had a brand new converter blow up. When the converter shop cut it open right in front of me they said it was a stock converter. What I bought was a TCI towing heavy duty converter. I installed it myself so I know it was not switched. WOW was all I could say. So they built me a custom converter and since have had no issues at all. SO lesson learned was not to trust everything even though it is "NEW". Check for bad welds and defects on everything you buy..
Side note= If your flexplate is on backwards the mounting for the converter would create a big gap! I thinks ??

[bk2life]

explain this wobble? motor running you see it move? or you can grab it (motor not running) and move it in and out? because the flex plate is just that, a FLEX plate.

please describe more.

how many miles have you dirven it befoire you realized the wobble?

[jclimie]

wobble occurs when motor is running. I shimmed it .060 and it seems to be better. I had my transmission rebuilder come look at it and he said it looks fine. Only put 20 miles on it maybe.

Originally Posted by bk2life

explain this wobble? motor running you see it move? or you can grab it (motor not running) and move it in and out? because the flex plate is just that, a FLEX plate.

please describe more.

how many miles have you dirven it befoire you realized the wobble?

[jclimie]

I shimmed it .060 and it seems it made it better but still a little wobble.

Originally Posted by TBONE1964

Be careful with this. The gap is there for a reason. With heat, the TC will grow a little(expand). It is not noticeable but it does. If there is not enough gap, the TC will push the crank shaft forward and wipe out the thrust bearing in the engine. Also it will wear out the front pump in the transmission. .120 is just shy of an 1/8 inch. make sure you do this according to the specs. I would hate to see your newly rebuilt trans full of metal shavings or worse.

[bk2life]

Originally Posted by jclimie

I had my transmission rebuilder come look at it and he said it looks fine. .

if he warranties this wobble in 10k miles then you are good to go..