Author Topic: Trans availablity?  (Read 698 times)

Offline Stewart G Griffin

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Trans availablity?
« on: December 21, 2019, 05:12:40 PM »
Which engine trans combos were available from say 83 and up?

73-81 was Th-350/th-400 so, pretty simple.

83-up
Th-400, depends
700R?
4L80?

Have to make a move soon, thus asking a lot of questions.
Thanks.

Offline zieg85

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Re: Trans availablity?
« Reply #1 on: December 21, 2019, 06:01:31 PM »
TH350C was up through the 1985 at which the only non-OD automatics was the TH400 even in the 4.3L V-6.  The 4L80E started in 1991 I think
1985 C30 Custom Deluxe Ext. cab 5.7L TH400 3.21 
1985 C20 Scottsdale 7.4L 4 speed 3.21
1986 C10 under construction
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Online MIKE S

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Re: Trans availablity?
« Reply #2 on: December 21, 2019, 06:04:57 PM »
I can only speak for Trucks sold new in Calif. The only automatic transmission available in 1/2 ton and light duty 3/4 to V8 vehicles is the 700R4 from 83 on. 400 was available on HD 3/4 and up until the end of the RV run. Manual transmissions were not available in light duty V8 vehicles either. Also the 305 was the only available V8 engine in LD 2wd Pu up to 1986. 350 was the only available V8 engine in LD 4wd Pu up to 1986. 
« Last Edit: December 21, 2019, 06:07:16 PM by MIKE S »

Offline Stewart G Griffin

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Re: Trans availablity?
« Reply #3 on: December 21, 2019, 08:07:07 PM »
i also wanted to clarify that i meant engine/trans availability in suburbans only.

We might as well go from 73 on up----even after 91.

Offline SilverMiner

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Re: Trans availablity?
« Reply #4 on: December 22, 2019, 07:03:58 PM »
i also wanted to clarify that i meant engine/trans availability in suburbans only.

We might as well go from 73 on up----even after 91.

Wow, actually a more difficult question than it really should be. My "go to" source is always the definitive material of the Vehicle Information Kits from the GM Heritage Center. But when it comes to transmissions, things are murky. From 73-79 their docs do not distinguish between different flavors of 3-speed autos (TH350 vs TH400) merely designating all of them MX1. For 1980 the TH350C was introduced but no specific mention is made of this in the documentation, just MX1 once again.

A quick check of the 1986 Suburban VIK does make clear in the text which model got either a 4-spd Auto vs a 3-sp Auto so by inference we know which got 700R4's vs a TH400 but that is only because internet lore tells us the TH350C ended before then. I haven't checked the 1991 Suburban VIK to see if it bothers to specifically call out the 4L80.

Engine info is specific down to 2bbl vs 4bbl and displacement, but trans info is less clear. Even the transfer cases are specifically called out, not sure why GM couldn't be bothered to do the same for transmissions. Check out everything here:
https://www.gmheritagecenter.com/gm-heritage-archive/vehicle-information-kits.html

Offline Irish_Alley

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Re: Trans availablity?
« Reply #5 on: December 24, 2019, 08:16:51 AM »
looks like they came from the 305-454 and 6.2. they came with the th400, 700r4 and the 4l80e. not sure about the th350 but i doubt it
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Offline fitz

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Re: Trans availablity?
« Reply #6 on: December 25, 2019, 10:29:57 PM »
I'll toss the SM 465 into the ring.

Offline 75gmck25

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Re: Trans availablity?
« Reply #7 on: December 27, 2019, 07:26:21 AM »
Also, some of the GM combinations seemed to be a little illogical.  My K25 is an 8400 GVW with Camper Special package, 14 bolt FF, HD springs, etc., and I initially assumed it was probably a TH400.  However, I found that in '75 they still used the TH350 on my truck.   The TH400 was readily available, so why not use it in a '75 3/4 HD vehicle? 

Based on a post from a guy who was doing a swap, apparently there were also years where they used a TH400 behind the 6 cylinder engine, which is total overkill. 

My Dad was a car salesman in the 70's and 80's, and he said that when you got to the model year changeover there were sometimes weird drivetrain combinations.  For example, if they were going to phase out a transfer case the next year, but had a few left in stock, they might carry it over the first month of the next model year, so you ended up with a combination that did not match the official documentation.

Bruce

Offline Irish_Alley

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Re: Trans availablity?
« Reply #8 on: December 27, 2019, 08:27:18 AM »
some 1 tons (think 77ish) got the inline 6. so i would imagine that truck would also get the th400 or manual
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When you have eliminated the impossible, whatever remains, however improbable, must be the truth ~Sherlock Holmes