1970 6 speed work in 1989

[Randal Barrick]

I'd like to add an overdrive on my 1989 K2500. Does the 6 speed from 1970, of the same model, work without major rework?

Appreciate all your advice.

[HO455]

Welcome aboard!
I think you have posted your thread in the wrong section. This is the lonely 67-72 Suburban section.
Ask a moderator to move your post to the 88 to 99 GMT400 section for better results.

[LockDoc]

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Maybe it is a mistype but none of the '70 pickups had a 6 speed transmission.

I will move your thread to the '88-'99 pickups forum.

LockDoc, Moderator

[Randal Barrick]

Opps, meant will a 6 speed from a 1990 work in a 4 x 4 1989 2500?

A buddy of mine has 1990 2500 4 x 4 and it's a 6 speed.

[Just call me Sean]

If it is a 6 speed it didn't come with it stock.

[special-K]

During the 88-98 truck run the manual overdrives were 5spds. Find out what that 6spd came out of. It should be possible to use it in an '89

[Randal Barrick]

My friends 1990 2500 is a 5 speed, not a 6 speed as noted earlier. So is the correct description a 4 speed with overdrive or 5 speed?

So the question is will that 1990, or similar, swap into my 1989?

I'm heading down to Napa to pick up the 1989 in a few days. Will be checking everything, then heading back up to Medford. Road Trip!

[Second Series]

I’m pretty sure it will work. Both my ’88 k2500, and ’90 k1500 have the 5LM60/NP241.
’88 to ’98 used this transmission with a few different versions. HM290, 5LM60, NV3500. From what I understand the case is the same but the internals were changed. The 5LM60 is not something that can be rebuilt at home, it has 3 rails that require a jig and the use of an oven to heat up some plastic things. The NV3500 was introduced in ’93.

[Randal Barrick]

Question: Which transmission vendor has a good reputation? Looking to buy a MG5 4 x 4 5 speed K2500 rebuilt.

Thanks.