Chevy question

[Hypoid]

"I'm asking for a friend." LOL Any way, he has a '79 Blazer 4wd with auto tranny, the tranny went out.

I checked Western tonight because they just set out a 'burban. I asked at the counter about interchange, the guy said "TH-350, '69 through the '70s" I asked about the 'burban, he sounded uncertian, said it was not yet in the system.

I walk back to the 'burban, it's an '87 and right next to it is another '87 truck. I also found a '75, which should be a drop-in, but looked very tired.

My question is this: When was the TH-350 discontinued?

TIA

[colomil]

If I remember correctly, GM started using the 700R4 in the early 80's to replace the TH350. The TH400 was used until the early 90's. You will need to get a tranny that came from the same transfer case. Output shaft length and spline count differs based on the xfer case used. Best bet would be a TH400 with a NP205 but that combo is somewhat uncommon. Next best would be a 700R4 with a NP208.

[1freaky1]

I had what was called a lock up t350 in my 85 Chevy cost double to rebuild too. Did not look any different on the outside so I did not know until had it rebuilt. Not sure Mike on what all years they used them.

[gm4x4lover]

they went longer in the trucks than i thought. My guess was 83 or 84, but looks like it was 86.


Around 1980 a lockup torque converter was introduced; this transmission was phased out in 1984 in GM passenger cars for the 700R4. Chevrolet (http://en.wikipedia.org/wiki/Chevrolet)/GMC (http://en.wikipedia.org/wiki/GMC_%28General_Motors_division%29) trucks and vans used the THM350-C until 1986. The lockup torque converter was deemed unpopular with transmission builders - B&M Racing once marketed a conversion kit for THM350-Cs during the early 1980s until the advent of high-stall lockup torque converters when its overdrive counterpart (THM700R4/4L60) were modified.

[Even 11]

IIRC; the TH350 was re-done as a 350c in 81 so if you can find one from before 80 you should be good. 82 was the first (and the worst) year for the 700r4. If you go with a 700r4, try to get an 89-92 one they are the strongest.

-Dane

[gm4x4lover]

IIRC; the TH350 was re-done as a 350c in 81 so if you can find one from before 80 you should be good. 82 was the first (and the worst) year for the 700r4. If you go with a 700r4, try to get an 89-92 one they are the strongest.

-Dane


The latter 700's are different than the earlier ones as they were designed to work with the computer. the earlier 700's are best to stay away from them unless built by a very good tranny guy. If you dont need the OD i would do a th400 for the strength and reliability.

[Hypoid]

Thanks for the replies!

I told him about the '75 down at Western, how much they wanted if he pulls it. He shook his head and said "ef that!" I think he already has a buyer lined up for the 'ol rust bucket.