Moparts

727 woes

Posted By: dcr

727 woes - 07/31/11 11:02 PM

Just got back from mo power event at martin brand new car and engine this weekend worked very well all in all ran number off trailer was blessed with a red light first round thinking cool free time trial cut good light took off shifted 2nd right at proper shift point but slipped for about 700 prm before it hooked eased out of it shifted to 3rd and lost every thing coasted off track to ticket booth still no gears let car set a couple mins started and took off seemed fine hit second nothing,coasted some more not quite enough to make it back to pit spot ,refired worked again got it to trailer checked fluid good,checked shift cable adjustment good went to back up seems as soon as I eased of throttle lost all drive. I was able to drive it on trailer and off trailer into garage when I got home any ideas dont really know were to start Im thinking converter or pump what do you think?
Posted By: Cab_Burge

Re: 727 woes - 07/31/11 11:43 PM

Check the shifter adjsutment again, make sure it(the cable end) drops into the shift arm easily in 1st,2nd, and 3rd gear I had the same sounding problem two weeks ago when I installed a new trans. blanket, the blanket was limiting the shifter arm and it ended up not shifting properly, I ended up adjusting it the wrong way once and it would not go into 2nd or high gear at all , I ended up loosening and rerouting the blanket away for the shiter arm on the valve body and readjusted the shift cable end so it drop into 1st, 2nd and high gear and it works fine now Two races(15+ runs) so far with flawless results
Posted By: MR_P_BODY

Re: 727 woes - 08/01/11 12:52 AM

I would look at the pump drive lugs... might be sheared
off with enough friction to just turn the pump without
any heavy load
Posted By: MRMOPAR

Re: 727 woes - 08/01/11 01:11 AM

Based on first hand experience with this with MR_P_BODY
Posted By: '72CudaRacer

Re: 727 woes - 08/01/11 02:01 AM

with both of these guys. My first thought was a fresh install and converter was not all the way in. Just a guess.

Brian Dunnigan
Posted By: rickraw

Re: 727 woes - 08/01/11 02:11 AM

i agree with mr.p. i'd check line pressure first. then drop the pan & check for debris. any metal, u know what u gota do.
Posted By: dcr

Re: 727 woes - 08/01/11 03:25 PM

Thank you for the pointers Ill check them out would it be possiable for flex plate to deflect enough to cause that problem or maybe shim converter back some it is a sfi plate but I did not measure how far I had to pull converter forward to attach to plate but it did not seem excessive.
Posted By: JohnRR

Re: 727 woes - 08/01/11 04:54 PM

Quote:

Thank you for the pointers Ill check them out would it be possiable for flex plate to deflect enough to cause that problem or maybe shim converter back some it is a sfi plate but I did not measure how far I had to pull converter forward to attach to plate but it did not seem excessive.



Highly doubtful this is the issue .
Posted By: dcr

Re: 727 woes - 08/01/11 05:17 PM

Quote:

Quote:

Thank you for the pointers Ill check them out would it be possiable for flex plate to deflect enough to cause that problem or maybe shim converter back some it is a sfi plate but I did not measure how far I had to pull converter forward to attach to plate but it did not seem excessive.



Highly doubtful this is the issue .

Im sure there is damage just trying to figure out what may have caused it so i dont have a repeat.
Posted By: MR_P_BODY

Re: 727 woes - 08/01/11 05:35 PM

Quote:

Quote:

Quote:

Thank you for the pointers Ill check them out would it be possiable for flex plate to deflect enough to cause that problem or maybe shim converter back some it is a sfi plate but I did not measure how far I had to pull converter forward to attach to plate but it did not seem excessive.



Highly doubtful this is the issue .

Im sure there is damage just trying to figure out what may have caused it so i dont have a repeat.



The only thing I can think of in the aspect of the
converter is if you have a mid plate on the engine
and the converter mounting points werent made longer
for the mid plate... with a mid plate it pushes the
trans back and the converter is still in the stock
location in relationship to the crank/flex plate...
I have a .090 steel mid plate and never had any issues
with the stock location... granted its .090 less
engagement into the pump
Posted By: Leigh

Re: 727 woes - 08/02/11 12:29 AM

Since you made one clean pass. converter lug failure is iffy, although possible. You didn't say if revearse worked. If it did, look for rear (forward for the GM folks) clutch failure, or, front planet failure.
Posted By: dcr

Re: 727 woes - 08/02/11 02:45 AM

Quote:

Since you made one clean pass. converter lug failure is iffy, although possible. You didn't say if revearse worked. If it did, look for rear (forward for the GM folks) clutch failure, or, front planet failure.

Made several clean passes before failure and yes does work but also fails the same as the forward gears.
Posted By: rowin4

Re: 727 woes - 08/02/11 02:55 AM

Dan, unbolt the converter from the flex plate and push it back into the trans, there should only be about 1/8" if more that's what caused the problem.

Posted By: dvw

Re: 727 woes - 08/02/11 03:20 AM

Loss of pressure. If there is enough fluid I think the filter is plugged. If it is on a new build there must be a catastrophic failure causing that much debris.
Doug
Posted By: Rapid588

Re: 727 woes - 08/03/11 03:08 PM

Does sound like possible front pump gear lug failure....

One thing a lot of people neglect to do on a new converter and/or pump gear replacement is to take the pump gear with the lugs on it (just the inner gear part) and set it on your converter, indexing it like it was installed.

Then take a feeler gauge and see if you have ANY clearance between either of the lugs and the converter indexing slots as you put pressure by turning the gear clockwise (converter snout facing up)like when engine is running.

If there is ANY clearance, then you have a high chance of having a pump drive gear that will shear the one lug off that is taking 100% (all) of the load.... and then takes off the other one to complete the failure.

I have seen plenty of mismathes.... could be either the converter snout (index) or the pump gear.


Most (not all) of the stock gears have an undercut on the lug drive tangs..... you can get the better non undercut and beefier units thru the aftermarket .... good insurance to have (still check the indexing tho )

CRT heavy duty pump gear here ----> https://www.coperacingtrans.com/product_...813251b82ea2bd7

Randy
Posted By: dcr

Re: 727 woes - 08/08/11 03:30 AM

Well I got ambitious and pulled pan full of metal particles removed and dissassembled found frt clutch pack totaly gone and burnt up appears while running it would suck up metal and plug filter and after allowing to sit enough would settle out to give it a gulp of fluid and let it move again.Every thing other then that looks good any ideas what might cause that to happen one speculation ive heard is the 2.9 ratio arm needs to be bumped up to a 3.8 or 4.2 maybe im asking to much from a stock trans with a valve body update but im out of funds for a good unit at this time so i guess Ill keep saving for a good trans in the meantime ill try another clutch pack that I have and see if I can make it through one more race.
© 2024 Moparts Forums