i have a 1990 chevy C1500. the transmission- 700r4 lost 3rd and overdrive. i bought another 700r4 from a private individual for 300$ and it turned out to be a bum tranny as well. is there some other transmission out there that i can swap for the 700r4? or what can i do as an easy fix to fix my original? is it something simple?
The 700R4 is a good tranny, most fail from abuse not use. Take the time to get 700R4 rebuilt or get a good used one. You want a 87 or later model as it has the latest mods to it. The newer 4L60 is nothing but a electronically controlled 700R4. I have a 700R4 in a 89 4x4 burb that I bought new. It has more than 180K on it and trany still works like a champ.
----------------- TheSnoMan.com
That might be true of the later ones, but the reliability and quality of many of the earlier 700R4's leaves a lot to be desired. Had a new '83 Chevy
1/2 ton with a 700R4, two complete failures within 3 years. This was just light duty around town driving. Dealer replaced with Turbo 350 eventually. Friend's '84 GMC same story....I think by the mid-80's they were more reliable.
There was two major revisions to the 700R4, one was in late 1984 and it was the biggest and most important revision becaue for some reason prior to this revision GM decided to route most tranny fluid around cooler in OD and converter lock and restirct tis flow to which let trannies do a slow burn. Another in 1987 dealt mostly with shift quality issues and that was its final version minus a few tweaks. No way I would consider swaping in a THM 350 for a 700R4. Properly built a 700R4 can easily handle a big block and then some.
----------------- TheSnoMan.com
I had an '83 Chevy 1/2 ton with a 305 V8 that did the same, after the second one I put a TH350 in it. Never failed after that.
Brian
Take the original to a GOOD independent transmission shop. Have them rebuild it using the newer aftermarket heavy duty parts. That will include a heavy duty sun gear shell carrier, larger apply piston, bored and sleeved valve body, and the newer clutches. Replace the converter with either a new or rebuilt. Power flush the cooler loop as well. Install an auxiliary trans cooler as well.
Expect to pay 1200.00 - 1400.00 for it. Or buy one from a good company that is already built with the good parts. I also recommend using synthetic fluid as well.
The catch with dropping a TH350 or TH400 in there is that you will lose OD and probably 3-4 mpg with it.
Isn't there also an issue with the 700r4 being electric and the TH400 not? That is what I was told when I had had enough of my old truck eating transmissions or at least after I put in the forth one. I did buy a used one out of a wrecking yard and it worked great untill I got into an accident about a month ago and totalled it.
Al
thank you to all who answered my request. i still am not sure what i am going to do with it though. i only paid 250$ for the whole truck with the bad tranny. so i dont want to dump a 1000$ into just the tranny.
mic SD Ca.
Well I got a good 700r4 from a wrecking yard for $400
MotorsForum website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.