89 C 1500 with a 400 trans from factory??

[TQS335]

Hi. I have a stock 89 C 1500 5.7 that apparently was built with a TH 400 transmission instead of a 700R4. I thought all the trucks in this series came with the 700? Any info is appreciated. Thanks.

 

[evilunclegrimace]

It was possible to order the THM 400 in the early year trucks. Check your RPO tag in the glove box and see what it tells you.

 

[stutaeng]

I think in those years it's very possible. I've looked at the literature from 89 and 90 and they list a 4 speed or 3 speed on 1500s and a 3 speed on the 2500/3500.

The only 1500 that I know for sure got the TH400 is the 454SS.

I think GM mixes and matches parts on outgoing models when the new body style models start rolling out... probably to clear their inventories.

 

[tpass]

Didn't they call them 3L80's in the late 80s early 90' til the 4L80's came out in 91?

 

[stutaeng]

Yes

 

[PlayingWithTBI]

FWIU in 90 GM changed their identification of transmissions. As example the 700R4 was a 4 speed, Linear drive, rated for 6000# vehicles so - they became a 4L60, the TH400 then was changed to 3L80 and so forth. Once they became Electronically controlled, GM added the "E".

 

[Schurkey]

Option code M40 at one time. I think that changed by the time the GMT400 series trucks were produced.

 

[someotherguy]

TH400 (3L80) came in GMT400 2500 (8 lug, not 6) and 3500's 1988-1990 until the 4L80E was introduced in 1991.

However, some early 1500's got them, too. Not common at all but they do exist. I had a 1988 RCSB C1500 parts truck with the 3L80 and 4.3 V6, all original.

Richard

 

[df2x4]

I had a 1988 RCSB C1500 parts truck with the 3L80 and 4.3 V6, all original.

That's the closest factory combo I've ever heard of to my red truck's current setup (4.3/4L80E).

 

[stutaeng]

I seem to recall some 2500 Express Vans had a 4.3 Vortec + 4L80e, no?