Can anyone tell me why my 700r4 just recently swapped, will not move in reverse unless I give alot of RPM. Forward gears seem o.k. Seller ***ured me it was recently rebuilt, and showed me a recent receipt. Did he rip me off or is there something I'm not knowing?
reverse takes more fluid pressure to operate than drive gears. Weak or incorrect pump is your problem. Early pumps were 7 vane, then 11 or so. Late pumps are 13 vane, and some of the later pump housings look similar, but wont work well in an early case.
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How fast is your idle? I know that when my carbed V8 is on it's fast idle cam before it is warmed up, the trans senses the higher rpm and the clutches engage slower to keep the trans from banging in gear. The older ******s like the TH 350 would bang hard into gear if the idle was high, but I have noticed that some of the later ******s seem to slide into gear more gently if the rpms are up a bit. The ******s in the snowplows at work will not let them go into gear at all if you have them still on the fast idle lever while warming them up. I know the TV cable on a 700 R4 controls the pressure and shifting when in normal use, but does it affect reverse also? maybe the cable could be checked? You could have other troubles, or something like too much air and not enough fluid running thru because of a fresh installation.... Sometimes you could spend a lot of time adding quart after quart until all the systems are full again..? before it acts like a normal trans again.
do you guys make up answers on the 700 trans? .... if the trans operates good in forward gears , the pump has enough pressure to operate reverse. Reverse is created by 2 clutch packs... the reverse input clutch and the low/reverse clutch pack. Often on a cheap rebuild the low/reverse piston is not removed from the rear of the main case. This piston requires a special tool to remove the retainer and springs. The seal may be hard and not holding pressure. It is also possible the rebuilder did not install the check balls properly. Depending on the year of the trans , the check ball count is slightly different. Check shifter position too, if the shifter is only partially in reverse , the trans will act poorly.
some what hard to fold over a square cut seal on the low/reverse piston i was mentioning. they may have done that to the reverse input clutch pack... or left off / cut the sealing rings on the stator support.. the possibilities what the problem is could be very high. I am curious if this was a DIY parts replacement on the trans or a rebuild by a knowledgeable trans person.
Maybe check the pressure port and diagnostics b4 teardown. Buy the manual on ebay. Buy 4 of those shallow clear rubbermaid containers at Walmart (12x18 or so). Take the damn thing apart and re***emble it exactly as described in the manual after you have verifed the content per the manual. Etc. Take it slow and enjoy your education. Then post answers like this on the forum. BTW, many of the "special tools" can be easily homemade with s**** and thought.
sorry yes I was refering to the one on the clutch pack....... the rubber(I think ) backwards V shove it in one. not the square teflon(I think) ones. but if you dont cut those right theyll leak as well and yes I speak as a DIYer with help from a pro. I got to redoo this ****** over due to the folded seal. Ill garentee you I wont EVER do that again. learned alot. My profesional helper Told me after it was done that that was one of the more difficult trannies to do and not to fear the others. the folded Seal netted me a total 90 # in reverse. nowhere near enough. I also had installed the Transgo kit
Wasen't it James Brolin that made those old AAMCO commercials? Give that dude a call, he probably ain't doing anything else.
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