Our '91 GMC 3+3 (Crew Cab) 1 ton pickup truck has a Hydra-Matic transmission. Ser# 91BAP18523 Another Number: 9677104 4
Is this a 700R4?
It seems to be a 3 speed plus overdrive.
Thanks for any info.
(Trying to tame the guzzler)
Is this a 700R4?
Jan 03, 2006
10 Replies
I think its classified as a 4L60...later became the 4L60E(E for electronic controled).
They didn't have 4L80E's in '91!
The 4spd Auto available in '91 on ALL trucks IS the TH700R4 which was also badged 4L60!
What is the shape of the trans pan?
Square = TH700R4
Square with 1 angled corner = TH350
Pan with a similar shape of Texas = TH400
Look at this link for exactly what they look like -
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That would be my bet. My 91 3/4 ton suburban has a 350 and a 4L80E trans. It was the first year it was offered in heavy duty emissions, light duty trucks. So if you have 4 positions on the gear selector then it is a 4L80E is not then it is a TH400.
mark
'91 was the first year for the 4L80E
'93 was the first year for the 4L60E
-Bret
I just had a look at the pan, and the drawings on
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do not match. I'll have another look at the casing for more markings. (It's on a bench right now) Or I could send a photo if anyone is interested. My email address looks like it is munged, but works the way it is.
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