Transmission Help

[molsenice]

The victom: 94 GMC 2500 4wd engine is 350.

 

cause - stupidity - went to save a kid who burried his truck in a mud hole - we got him out but there was a snap sound and now I have reverse only.

 

I'm sure I need a new trannie - but have no clue what is in there - spent most of today lookin on the web and crawling under the truck looking for numbers to no availe

 

finding a used one or having this one rebuilt sem to be my options - how hard are these to rebuild?

[molsenice]

ok - caled the dealership and gave um the last 8 digets of the vin# - looks like the trannie is a 4L60E or (M30) for short.

 

next problem is that it was in a ton a chevies / gmc's both 2wd and 4wd.

 

I can not seem to find out what eh diferrance between the 2wd and 4wd version of the 4L60E would be - if there is no biggie differance - than I'm good - got a bud who might be able to set me up

[irengineer]

Fran,

 

Couple of things. 4L60's generally don't go in 2500 HD's, they are 1500 series truck transmissions (and go into most RWD GM car applications as well). The typical 2500 trans in 94 would have been the 4L80. There is an exception to the 2500 / 1500 rule, though and that is for a 2500 with a lower GVW than a typical 2500. The GVW of the 2500 models that used to get the 4L60 was 8600 LB, so you might want to double check your trucks GVW sticker to verify the dealers info. You may also find an RPO sticker that lists all the major content of the truck and look either for the M30 or MT1 RPO. In today's trucks the sticker is in the glove box. Not sure if they were on the 94's but if not in the glove box it could also be on the door or under hood near the rad support.

[95Sierra2500]

If you've got the 'light duty' 2500 then you got shafted with the 4L60. The difference between the 4x4 and the 2wd version is, as far as I know, the tailpiece. On a 2wd version it will come down to basically a point with a yoke sticking out, while a 4x4 will have a shaft in the center with a flange to attach to the transfer case. Thankfully, these housings can be interchanged fairly easily. However, I am not so sure about the output shaft. I've never had to do it myself.

 

If I were you, however, I'd look into the feasibility of putting a 4L80 in there. It's a much stronger trans, should bolt right to the engine with a simple flexplate swap (if even that - I can't recall offhand), and you may have to change trans mounts. I also don't know about shift linkages. However, it's definately worth considering.

[molsenice]

irengineer and 95 seirra 2500 - thanks for the feedback - just went buy the vin number from the dealer - I got the truck with 60K miles on it and never suspected anything different - I'm thinking I might want to pull the trannie to double check what it is - as far as swappin in a 4l80 - I can chop and weld the trans mount and as far as the drive shaft mods - hey - i could get that too. - I happen to be handy - just finished a complete jeep build - learned alot with that.

 

bottom line is this has been a very tough, dependable truck, in teh last couple a years, the major things that tend to go wrong have and they have been fixed

 

New 4wd wire harness, fuel sendin unit, alt - starter, head gaskets, brake lines. tires and brakes are new sooo, fixin / replacing the trans would be cheaper and better than replacing the truck.

 

I have a buddie who ownes a salvage yard and he has a couple 4L60 trans from 2wd vehicales - he, like I figure we have till mid November to look for a 4wd version to avoid the tail peice swap - not sure what is involved there, figure it is better to wait than to anoy - prices go up if yer pita

 

thanks again for the feedback - I think I will go ahead and pull the trannie - just to be 100% possitive what I have. - been under there, just couldn't see anything to id it on the pan

[molsenice]

Just double checked - trucks GVW is 7200 - RPO number in the glove box does show an m30 - hey - been a good truck, tough, no complaints.

 

now to figure out how to be pacient or to swap out the tail stock on a 2wd version to make a 4wd with my tail peice

 

 

 

who thinks they might know what let go??? - I was yankin a kid outta a mud hole and got a little heavy on the skinny - and heared a snap - still have reverse, no forward