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View Full Version : Help! Tranny Specialists - 700R4 Cases & Etc



ZZ
01-23-2005, 12:59
I know have discussed this in other threads, but I've to got to do something soon.

As some of you know, I have had 700R4 problems now for over a year. This started in 12/03 when the original went out. I was in a big hurry to get it back on the road with my job at the time. The tranny shop offered to rebuild a gasser 700R4 with a new diesel TC. The warranty for it was 1 year. When I got it back it shifted too late and too hard for my liking. The only way that they got it to my liking was to somehow modify the governor. It worked well here in town, but it was squirrley shifting up & down between 3rd & OD on the road between 32 - 45 and then the TC wouldn't lockup after a few highway miles. It lasted like this for about 7 months and then started slipping.

The shop worked it some in June and then they did a complete warranty rebuild last July. They claimed that they put in a new low stall diesel TC. They used the same modified governor this time. They also wired the TC lock direct to ground to bypass the electronics. It seemed a lot better, but it was still shifting squirrelly between 3rd & OD on the highway.

The warranty expired 12/18/04 and then it went crazy earlier this month. One day I was on the road at 65 /w cruise and it dropped down to 3rd for no reason.

I took it back to the shop and they said that since they had to work on 3 times during the warranty that would honor the warranty and rebuild it one more time.

Now for the questions...

They say that they want to find another case that came in a diesel pickup, and then rebuild it. Does it really make any difference if the box was a gasser or a diesel?

I've considered getting a rebuilt TH 400, but the tranny tech said that I definetely would not be satisfied with it because of the gearing and no OD. Is high gear in a TH 400 about the same as 3rd in a 700R4?

I can't do any of the work myself. We only have two shops locally. The other shop won't guarantee their rebuilds in 4X4's because of the mud hog guys around here, so I won't go there.

Sorry about about the long post. I wanted to pass along as much info as I could. smile.gif

britannic
01-23-2005, 19:20
Ask them to rebuild it with the HD 'K' case; it should have a large letter K each side of the bellhousing. Make sure you get HD clutch packs, HD pump, .500 TV valve, 'vette servo pack and ensure they install the correct governor for a GM diesel.

Check out the feature articles and other forum comments (use the search feature) for additional info.

ZZ
01-23-2005, 20:19
Thanks, I'll keep this all in mind. I still wish I could find the link for the hydraulic TC lockup change over.

JFleming
02-15-2005, 17:21
Yes, 3rd on the 400 is 1:1, same as 3rd on the 700.

Smart move to go with the K case, and all the HD goodies.


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Currently have 17 6.2's , 9, 6.5TD, and 1 BA 6.6+

john8662
02-15-2005, 18:32
This story sounds very similar to one I had with a suburban I once owned (yes, I do sell a vehicle sometimes), but I had a local shop rebuild the tranny. They swapped in another TH700 and didn't even think DIESEL. I got it back thought everything was great, until I punched the go petal. The tranny wouldn't shift until I let off the petal and back on again after a romp. Took it back to them, went for a test drive with the tech, and he told me it was my engine. Got it back in the shop and started looking for the fuel filter, I told him that it was a DIESEL and it was bumping govenor. They had put in a gasser governor, oops, this tranny didn't last either, they put the wrong TC in it. Just telling all this to side with you, it happens, if I had to do it again I would just go down and buy a dealer SERTA transmission.