What GM Transmissions Uses Locking TC Besides 700R4? [Archive]

05-28-2006, 17:09

That is which ones will bolt up & run on a '90 6.2L

My tranny finally bit the dust today. It went up in smoke and quit pulling today. I learned that heat is not the only thing that'll get to them. I don't what did, but it was running only 127 degrees at 60 MPH when she laid down.

I only have the one tranny shop that is close enough for me to really want to deal with and they never could get this 700R4 right.

mhagie

05-28-2006, 20:37

I have a newly rebuilt 700R4 for a 4x4 but I don't know if its what you would want.
Merle

DA BIG ONE

05-29-2006, 02:44

The 700r4 can be built to last as long as the case is of the latest design post 87. Many shops do changeouts instead of rebuilding and the poor customer gets stuck down the road because of a crappy case.

I had an 86 GMC Jimmy w/6.2 diesel and went to the turbo350 w/t-case adapter because the 700r4 was complete s___ at that time!

Many upgrade hard parts can be had cheap, w/kevlar clutches and premium steels being best. Clamping forces has everything to do with clutches lasting and any good off road/4wd valvebody should work here.

Want to spend some extra $$$$ go with a 4L60/4L80 and stand alone controller.

Good luck!

06-01-2006, 10:19

The truck went back in the Tranny shop Tues morning. They are rebuilding a different one (700R4) all together. They are giving me a $200 break since the last one they did crapped out so much. They are putting the Corvette kit in this one. I'm supposed to get it back late this afternoon or tomorrow.

DA BIG ONE

06-01-2006, 13:43

06-01-2006, 14:24

I hope so. I have my fingers crossed...

Robyn

06-01-2006, 20:26

My 700R went away in my 84 Blazer.
I bought an 87 "K" case 700 R from a 4x4 and built it myself.
There some real good books out there on 700 how to and what to use. I researched it well and bought most all of my parts off ebay except the converter.
Use a transgo #2-3 shift kit and a good cooler. Mine works wonderful now.
Good luck

06-02-2006, 19:49

I was able to pick up my truck late this morning. This tranny seems so much better than the previous one. At least the locking TC works as it should on this one. I don't like the first shift point. It comes out of low at about 17 mph, second around 23 mph and 3-4 around 38 mph. I can handle the other shifts, but I just hate having to hear the engine have to rap that hard coming out of low. It seems like it needs to shift around 12 mph.

The tech asked me not to try to adjust the TCC myself on this rebuild.

He also said that he used 7 clutches instead of 6. Is this a good thing?

What are you guys' shift points on your 700R4's???

Nelsoncat

06-03-2006, 01:24

How do you tell if you have the 87 and up case? Also what are the books for building the 700?
Thanks
Craig

john8662

06-03-2006, 07:24

The better 700R4 case has a large "K" stamped on the side of the bellhousing area, it's the more udpated version with a heavier case for 4x4's.

wthif

06-03-2006, 08:47

What are you guys' shift points on your 700R4's???

WOT shift points with 4.10 gears and 32 inch tires.
1-2 plus side of 20 (not sure where the speedo is; isn't my concern at WOT)
2-3 45-50
3-4 80+

With WOT I can hit the governor in the 1-2 shift if not careful but the rest of the shifts occur just before hitting the governor.

Regular driving (what is regular?) shift points change depending on throttle input, but my lowest 1-2 shift is around 10 mph.

06-03-2006, 17:24

Mine seems to be getting better as it breaks in. The 1-2 shift with a light acceleration is occuring now around 13-14 mph.

I have never ran my truck with WO throttle.

Nelsoncat

06-04-2006, 17:05

Do 2 wheel drive 87up cases have the K? If they do them I got boinked, if they don't how do you tell or are 2wd cases less desirable? What is different other than the case itself which is evedent to the eye?

Thanks
Craig

06-04-2006, 18:10

I drove my truck today on a 120 mile round trip with this rebuilt 700R4. The first sign of trouble was at a stop light. When the light turned green; I tried to take off. It was like it was out of gear and then jumped back in. The next trouble was stopping at a stop sign. It didn't seem like the TC was slipping as it should and it shimmied and almost killed the engine.

After things settled down; it now doesn't have 2nd & 4th gears and reverse doesn't work. It shifts from 1st to 3rd at about 25 mph and the manual locking TC still works after it goes into 3rd.

It's going back to the shop the first thing in the morning.

wthif

06-04-2006, 21:00

Any other shops?

I'm wondering if they set the kick-down cable correctly, because of your shifts out of 1st into 2nd. Did they check the line pressure after installing it? With little throttle it shouldn't go up to 17 mph. Unless they didn't set the transmission up for the lower revving diesel. Also sounds like the TC wasn't unlocking when slowing down.

Keep us posted.

john8662

06-04-2006, 22:40

Unless they didn't set the transmission up for the lower revving diesel.

Interesting, and it does happen!

There is a differnt governor for the Diesel, you'll have to specify because it's amazing that they can't figure it out.

Had this problem on a '91 burb 6.2. Took it in for tranny overhaul, nuthin but problems later. One of which was the governor wasn't right.

The way to tell was the 2-3 shift wouldn't happen when at WOT (florin' it). IT would shift from 1-2 though, but nigher.

Check it out!

Do 2 wheel drive 87up cases have the K? If they do them I got boinked, if they don't how do you tell or are 2wd cases less desirable? What is different other than the case itself which is evedent to the eye?

Have seen 2WD cases with the K on them, not sure if this is the norm for sure though. Got one of them with the K sitting in a friends' shop (it's mine, just can't put my grubby hands on it).

06-05-2006, 03:49

The cable seemed to be set close before all of the trouble.

There is only one other local shop, and he won't warranty any 4X4. He claims too many mud hogs caused him to be that way. My truck has never been out in the mud. It has had a "protected" life. I can't justify spending around a grand without any kind of protection.

wthif

06-05-2006, 09:35

The only reason I ask about the cable is it directly effects line pressure and if the trans isn't producing enough pressure it will fail quickly. Also if they didn't set the trans for a lower revving diesel they might have adjusted the cable to compensate and make the shifts more reasonable. These are just ideas and I am by no means an expert, but I did install my own trans with a little help from Britannic.

06-05-2006, 09:40

Thanks for the response. It is in the shop. The tech thinks that some kind of shaft broke.

06-05-2006, 16:13

I dropped by the shop mid-afternoon. The 1-2 pack had melted down. The reverse gear's splines were ground smooth. The tech told told me that he thinks the other tech somehow reversed the cooling lines when he installed it Friday. He showed me with compressed air that lines were open one way and restricted the other. He said that the external filter was probably causing that. He said it was likely not getting enough fluid.

He said that he put in a new 1-2 pack, reverse gear and a new TC and flushed all the lines. I hope that is enough. I'm supposed to get it back by tomorrow afternoon.

maxx

06-05-2006, 16:46

I hope this might help. I stumbled across this site, and there seems to be a lot of real good info. At this time I have not purchased anything from them, but I am planning to. www.redrider.us/700_raptor_transmissions.htm

06-05-2006, 16:54

Yes, I've read about them before. If what they say is true; they'd be hard to beat.

What scares me about long distance orders like these are having to hire someone to install them and then maybe having to pay them again to R/R if it failed

06-08-2006, 19:42

I got my truck back Tues night. He still had the TCC set to high for my liking. It wasn't too bad when I started driving it the first part of the day, but it gets the shift points way too high the more I drove it. The tech wouldn't set it back with the gas governor being in it. He said the pressure would be too low and it wouldn't last.

I took it on a 60 mile round trip today to my doctor and had this experience with it. It did fine on the 30 miles going, but was it was ever a different story coming home. I was coming back with it running 65 mph with the Cruise. Some Dummy pulled out in front of me and I had to hit the brakes. Thinking all was still well; I hit Resume at 45 mph. It started speeding back up and then passing gear kicked in and it dropped to 3rd. It would not go back into Overdrive at all. I pulled off for a few minutes and then tried it again. The shift points went crazy. 1-2 was at 27 mph, and 2-3 was almost 45 mph. I ran it up one time to 67 mph trying to get in OD and it just wouldn't do it.

The shop still couldn't find a diesel governor for it. So, I ordered a new one and got it today. I'm putting it back in the shop tomorrow morning to have him change it out. He said that with a Diesel governor that he would set it as low as I want it. I guess it's to be seen. Fingers crossed once again...

wthif

06-08-2006, 21:39

The pressure shouldn't matter with the correct parts and you're not going to want lower pressures; for the most part the higher the better. There are springs or something along those lines for diesel transmissions that control the WOT shift points and will make your transmission more desirable to drive with any amount throttle. Adjusting the pressure lower even with those springs will destroy the transmission in a matter of miles. With the correct parts, and the TV cable set properly shift points should be to your liking and transmission pressures should make for a healthy trans.

Hope it all works out this time.

john8662

06-08-2006, 22:55

Simple thought....

How FULL was the tranny fluid with the engine running and checking it hot?

If it's just marginally full, it can and will suck a bubble and behave oddly for awhile. Something like a fast hard stop could sure trigger that. Check this 1st, then intall the proper governor.

John

DmaxMaverick

06-08-2006, 23:39

Using a gasser governor and compensating the TV will give the results you are seeing. As Wthif said, pressure too low will kill the tranny, namely the low band. I'd suspect the tranny is already damaged, or wasn't assembled correctly in the first place, from your description. Even with the wrong governor, it shouldn't shift all over the RPM range, after shifting OK first. If this shop was competent, they should not have given it back to like they did, regardless of how many "Corvette" parts they put in it. While upgrade parts are mostly a good thing, comparing a Corvette to a truck is apples and oranges. The two have totally different missions, and the engines operate at opposite ends of the tach (read: opposite pressure curve). I wouldn't suggest putting any Corvette tranny upgrades into a truck tranny (if the truck is used as a truck). There are plenty of truck-specific upgrades available, at less money.

Now, the clutch thing.....7 is not necessarily better than 6. If they installed hi-per frictions with the Kolene stators, designed for more frictions, that would be different. You can't just add one more friction and call it good. You will never get the shifts street-able like that. The "more clutches" trick is fine for the track, but won't work for a daily driver, especially in a truck.

06-09-2006, 03:08

Thanks for all the responses. I hope I didn't damage it. I shouldn't have drove it last night. I am getting ready to drop it off early this morning so it will cool before they get there.

The shop I use usually does good work and their competantcy is usually very high. They do all the tranny work on our city owned vehicles and several local fleets. Most are gas burners. They admit they don't do a lot of diesels though.

DmaxMaverick

06-09-2006, 03:57

Shops that don't get much exposure to Diesel autos usually don't take the warnings serious. I've seen it too many times. Sounds like your tranny is providing some OJT. It's hard to believe they are having such a time with yours, since they service fleets.

I have a good friend with an excellent tranny shop, but I would do my own before letting him do a Diesel 700 overhaul. He just doesn't see enough of them, and has trouble with every one I've heard of him doing. I've done a few 700's in the last 20 years, both gassers and Diesels. The tranny in my '85 is essentially original. I installed an aftermarket kit, clutches, bands sprag, etc. in about '88. It wasn't failing, I just towed a lot and did a lot of mountain driving. I've killed several autos, and avoided killing that one. The best mod I did on it was a manual TC lockup. Since, I've never seen temps over about 200

06-09-2006, 04:18

I do have the manual lockup. Hopefully, that saved it yesterday.

They have promised to stay with me on the warranty till they get it right. They tried hard on the rebuild they did in Dec '04. That tranny never did have a diesel governor, but maybe since I bought a new one that worry will be over.

I'm getting ready to take it now.

06-09-2006, 04:51

I just drove it to the shop in low gear. I'm glad that it's only about a mile from home. I only pushed it up to about 20 mph one time. I hope they can do what needs to be done today. I'd hate to be without it 3 or 4 more days again.

06-09-2006, 12:23

They changed the governor. I had him to set the TCC back three notches after I got it back and test drove it. My shift points are to my liking now. 1-2 @ 11 mph, 2-3 @ 20 mph, 3-4 @ 34-37 mph.

He said the shifting problem this time was caused by the throttle valve being stuck. The last 700R4 they rebuilt for me did this same thing one time. So, maybe that won't happen again.

06-18-2006, 19:55

For those who are interested. They seem to have gotten everything right this last rebuild. I drove it on a 125 mile round trip last Thursday and a 240 mile round trip yesterday. The truck performed better than it has since I bought it in '03. This is the first tranny that the locking TC has worked right.

I learned a lesson through this. I spent a lot of good money trying to prolong the last tranny that was weak and never was right. I had two coolers, a deep pan and an external filter on it. The shop bypassed the coolers & external filter and put a factory pan on this one.