Transmission problems

[giterdunn]

Hi guys, I'm new to the forums. I just bought an 85 M1008 this month. The guy that had it swapped the turbo 400 with a 700 and it acts like it revs pretty hard to change gears. I'm pretty sure that it's the torque converter because it has a switch to manually lock it and when I lock it it drives fine. It's just slipping too much before it gears up. I think whats going on is that he got the tranny from something with a weaker engine, so it has a weaker torque converter and my engine is too strong so it slips. Has anybody had this problem before? He gave me the original transmission so I could switch to the original torque converter and see if that helps.

 

[Warthog]

Welcome to SteelSoldiers.

When you have time stop by the CUCV Wiki page and then the FAQ

Cucv - Steel Soldiers::Military Vehicles Supersite
http://www.steelsoldiers.com/cucv/20600-faq-thread-cucvs.html

The 700 is an electric lock-up tranny. It requires a computer or a manual switch. It also requires a Throttle Valve cable (can't remember the correct name). They need a Diesel torque converter to work properly.

Without knowing how he installed the 700 and if he used the TV cable, diesel torque converter, etc, you will be preaty much on your own, It will be trial and error.

There are a few guys that have done the swap, but each on is different as everyone has their own way of doing things.

The more details you can provide us, pics included, someone might be able to help. Did he tell you what type of vehicle he took it out of? Car? Truck? Year?

Do a search for 700r4 and you will find some good threads that may help

 

[burbn10]

Early 700R4's were hydraulic control. No electronics. The later 700R4/4L60E were electronic. To properly use them behind a diesel, you need a 1200rpm (Or less. 1200 was stock on the TH400 diesels) torque converter and a diesel 700R4 governor. TV cable may be out of adjustment also. I'd try adjusting that first.

 

[giterdunn]

Thanks guys, I'll check that stuff. I'm going to ask the guy what he got the 700r4 out of, but I'm pretty sure I just need to switch the torque converter. I have the original torque converter from the turbo 400 so that shiuld work. Does anybody know the parts #'s for the governor?

 

[burbn10]

Thanks guys, I'll check that stuff. I'm going to ask the guy what he got the 700r4 out of, but I'm pretty sure I just need to switch the torque converter. I have the original torque converter from the turbo 400 so that shiuld work. Does anybody know the parts #'s for the governor?

If you have access to a tachometer, you could do a stall speed test without ever taking the trans out. Hook up the tach, put the truck in gear with your foot hard on the brake and give it a good amount of accelerator pedal. The tach will stop at the stall speed of the torque converter. Only do this for a few seconds. Just long enough to get the reading from the tach. However, I don't think that is your problem. It sounds like governor or TV cable problems. I'm not sure on the model numbers on the governor, but just call any Chevy dealership with a parts department and have them look it up. Mid-80's civilian 1/2 tons came with a lot of 700R4s behind 6.2s.

 

[giterdunn]

Thanks guys, I just have got around to working on it, been busy at work. I got the transmission out and it definitely had the wrong torque converter, it only had 3 bolts to the flywheel. I know diesels are supposed to have 6, so now I'm having a hard time finding a diesel converter for a 700r4.

 

[burbn10]

Thanks guys, I just have got around to working on it, been busy at work. I got the transmission out and it definitely had the wrong torque converter, it only had 3 bolts to the flywheel. I know diesels are supposed to have 6, so now I'm having a hard time finding a diesel converter for a 700r4.

Don't buy this from the company's site. Go check around like Summit Racing or something like that. You could also call a GM parts supplier and get pricing on an OEM one from a 1/2 ton 6.2 diesel Suburban. TCI Auto: 700-R4 Maximizer™ High Torque Towing Converters 30 Spline

 

[giterdunn]

Thanks man, yeah I just ordered an OEM one form NAPA, except mine's a 27 spline. Aren't they supposed to be 6 lug? The only 27 spline diesel converter they could find at napa was a 3 lug.

 

[reloader64]

My 1983 civvy diesel 1/2 ton only has 3 bolts on the torque converter.

Scott

 

[ranchhopper]

Bought the correct six bolt torque converter from transtar in addison illinois for $100 I believe they are a nationwide company.

 

[giterdunn]

Okay so I finally had time to get a new TC and went ahead and replaced my seals and trans filter, bolted everything back up and adjusted the TV cable, but it still wont go into second. I'm good with diesels in bigger trucks and tractors, but I don't have a clue about automatic transmissions. I've heard that it could be that I need a diesel governor for the trans or that the vaccum pump is messed up, or something inside the transmission is wrong. It doesn't slip as much taking off but it still wont change gears. I was thinking it could be either one of the first 2 problems because it reved pretty high before shifting before it broke and both of those problems can cause that. My question now is is there any kind of tests I can do to determine whats wrong or do I just need to take it to the shop?

 

[ranchhopper]

Did you check the governer in the trans I had one that wouldnt shift it was the governer gummed up.