Is part #3975464 the new part number for the 2nd gen flexplate ? Repulic Diesel said #3946161 was not a good number & gave me the 464 plate . The plate looks like the one I took out of my 93 except it has a rough finish . My old plates last 3 numbers were 784. THANKS

 

Can't help you on the part #, but I do know that they are a bit thicker and are shot peened to relieve stress and make it take alittle more abuse.

 

Anybody have any info on those numbers? THANKS

 

Call any Cummins distributor/branch up and ask em for the 3946161 part number and if it has been superceded to 3975464 they will tell you right then.

 

yes, I just purchased the 3975464 from cummins they checked the 3946161 and superseded it to the 3975464.

I have to say I'm really surprised at how light duty it looks. even if it is peened, I'm really thinking twice about it.

btw, cost me over $200.00 with tax.

tks,
rjm

 

As found here ~ http://www.transmissioncenter.net/dodge.htm


OEM nested in the SFI one for comparison ~

 

Does this need a spacer to install behind a Goerend 15ss on a 91.5 ?

 

The 2nd gen flex plates are not hugely thicker than the 1st gen original so there shouldn't be a problem. Quickest way to find out is to measure the gap. Remove the dust cover, remove the TC bolts, slide the TC all the way back, then measure the gap between the flex plate and the bolt pads on the TC.

 

For around $150 you can get a SFI flex plate.

 

The PATC one ?

 

Dream on.

1835910 flexplate

$155 on FleaBay

NATCO transmission put one in for me. Said it looked good. Works good.

 

PATC platinum series flex plate goes for $169

edit: but i know nothing of automatic transmissions, so not sure if thats what you're looking at/for

 

I have had a 92-518 / 94-47RH/2006-48RE flex plates on a bench side by side at the same time. All three measured the same any where I used a set of mikes on them.

So in a search you don't need to be to picky.

 

Just anecdotal I know, but my son and I both shredded a flex plate. Both of us replaced it with an SFI plate. Neither of us have had any further trouble.

These engines can put out some hellish torque when you start messing with fuel and air to them. The tranny's can be made to handle it, and that involves tightening up on the TQ ratio and coupling. That actually takes some stress off the rest of the drive line, as the low gear torque available is actually less. The weak link now is the flex plate.

Back in the early days (1960 or so) when tolerances weren't what they are now, the flex plate had to compensate for slight mis-alignment, thus the name flex plate. At 100 ft/lbs or so behind a gas engine, that worked fine. Now you just need a strong coupling. Allowing it to flex just invites stress cracking.

It looks to me like the second gen flex plate is the same plate as the first gen, just shot peened, which leaves a finish resistant, but not impervious to stress cracking. Peening also can relieve some, but not all of the welding stresses in the plate.

The number I gave is the PRW specialty series SFI rated plate.

I notice a concern about fit. The TQ probably has +- .050" to .100" or more tolerance for axial position. As long as the TQ seal surface and transmission front seal are in good shape, flex plate thickness isn't going to matter.

 

No offense but out of all the people who "shredded" a flex plate, how many have considered the number of miles on it? 200K? 300K? They should be replaced every time your transmission is rebuilt in my opinion. When you rebuild an engine do you not replace most all the rotating assembly and wear items? Why chance a high performance engine by reusing the connecting rods and pistons just because they look okay.. Same with a flex plate That thing rotates non stop when the engine is running. You don't need to replace it with an "SFI rated" one, you just need to replace it

Just my 2 cents worth