geordi wrote:
I WISH that replacing the front pump solved this - it doesn't. It's even in the owner's manual as "normal" behavior of the Chrysler transmission, this delayed engagement or sometimes stalling is part of the drainback issue. I've replaced the front pump on my transmission and with a new converter from FTC.... It STILL does this randomly to me. The next time I drain the transmission for a change, I'm going to install the check valve on the cooler line. That seems to be the only confirmed fix.
That's very surprising; replacing the front pump assembly with the updated version did solve both stalling and drain back issues on my Jeep just as it did for some other owners on this forum who posted their results. It has never done it again after the install of upgraded parts.
BTW, I had already replaced the anti-drain back (flow-control) valve (Mopar PN 04799681) inside the transmission about a year before replacing the front pump assembly & torque converter and it DID NOT solve the stalling issue or the hesitation (drain back) issue when first starting off.
It is also been posted by some members on LOST that some of the cheaper brand transmission filters can cause the drain back (hesitation) issue.
Transmission Service Manual wrote:
Severe wear of the TC limit valve bore in the front pump housing results in loss of converter release oil pressure. Reduced release pressure at low speed and idle can drag the converter linings, causing engine surge, pulsation or stall.
The torque converter limit valve spring in the 45RFE, 545RFE front pump can often break. This valve limits converter release pressure. A broken spring can cause the valve to become stuck and result in converter clutch release issues including engine stalls at low speeds.
Chrysler vehicles equipped with 45RFE, 545RFE and 68RFE transmissions often experience TCC related troubles. These may or may not include trouble codes accompanied by TC clutch slip, no lockup, overheating and / or loss of fuel economy. In some cases, the TC clutches may be unable to release TC lockup, resulting in improper lockup functions and / or complete engine stalling.
Problems such as these can be caused by excess wear in the TCC switch valve bore, which allows vital control pressure to escape the circuit. Replacing the complete transmission oil pump assembly with a new updated assembly or reconditioning the bores with the proper tools and installing an oversized TCC switch valve kit can restore crucial clearances for renewed TCC control and operation.
From another LOST poster back in 2015:
viewtopic.php?f=5&t=72451amslube wrote:
I had the drainback issue about six months after I did the first transmission fluid/filter change. I read about the internal spin-on filter and the drainback issues associated with the anti-drainback valve. Well two filter changes later, one being with a new Mopar filter didn't change anything so I just lived with it for about a year or so. I finally decided to install the euro torque converter and at the same time replaced the front pump with the newer updated version pump. Luckily, I was able to find a brand new pump on Ebay for about half the cost as one from the dealer. Another note, when I inquired about pricing and availability from my local dealer, these pumps were on backorder. Sort of tells you they are in demand. I did the replacement of the torque converter and pump myself and it is now about a year and a half since the replacement and no drainback issues.
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