What transmission in 91 K2500?

[TennesseeZ]

It's the 6 lug, regular duty 3/4 ton, 5.7L, automatic. RPO MX0. 4l60e or what?

I'm thinking about putting a TransGo kit in it while I've got it out, don't know what to order. Looking to beef it up a little primarily for towing and longevity.

Suggestions?

[tallkid]

i belive in 1991 it should be a non-electric 700r4, unless its not an overdrive of course.

[timcrow00]

it should be overdrive, if it has a tv cable then its a 700r4 i dont think they started the 4l60e till 93. but if you dont have a tv cable then it would be a 4l60e

[TennesseeZ]

It's got the TV cable, I guess i jumped the gun thinking it was a 4l60 or something. I guess I'll just put it back in and do a valve body or shift kit later, I'm not going to take the transmission apart at this time.

[lurch115]

the 4L60E wasn't introduced in the trucks till '93, and MOST of the 3/4's would have a 4L80E in them. Which i believe was introduced about the same time.

[bwood]

The 700R4 is technically a 4L60. The 4L60"E" is the electronic version that is computer controlled and uses soleniods for the shifting duties. The absence of a TV cable in a 91 could also mean TH350/400. The 3 speed autos were still available on these trucks, but I've never seen one on a model higher than a W/T model. It's not uncommon to find them on V6 W/T also.

[munger]

4l80es were available at the time but mxo is the 700r4 and the tv cables proves it is a 700 by that time they had 700r4s strong enough to go in them

[69-350]

6 lug = half ton, no matter what the badges say. If it's limited to half ton engine choices, tranny choices, 8.25" IFS diff, and six lugs, it's a half ton. Only difference between that truck and a normal half ton is the fact that it has a slightly heavier leaf pack, and a 14 bolt SF. So does my 97, and it's a 1500. Somebody here on the boards used to be a GM engineer and explained it all to me, basically GM liked to put 2500 badges on trucks for awhile. Either way, if it's 6 lug, it's half ton, no matter what anybody says. If it smells, tastes, looks, and feels half ton, then it is one.

And bwood is right, by GM's naming convention, a 700R4 is a 4L60; 4 forward speeds, Longitudinally placed, 6000 GVW. And no half tons had a 4L80, with a few exceptions, which I'm not 100% sure on, but I believe they would include something like the Vortec Max trucks, although I want to say they had 4L65E's, or maybe 6.2L vehicles, although I'm just guessing on that. Otherwise, your standard half ton pickup would not have had a 4L80.

[dmnall]

Originally Posted by 69-350

6 lug = half ton, no matter what the badges say. If it's limited to half ton engine choices, tranny choices, 8.25" IFS diff, and six lugs, it's a half ton. Only difference between that truck and a normal half ton is the fact that it has a slightly heavier leaf pack, and a 14 bolt SF. So does my 97, and it's a 1500. Somebody here on the boards used to be a GM engineer and explained it all to me, basically GM liked to put 2500 badges on trucks for awhile. Either way, if it's 6 lug, it's half ton, no matter what anybody says. If it smells, tastes, looks, and feels half ton, then it is one.

And bwood is right, by GM's naming convention, a 700R4 is a 4L60; 4 forward speeds, Longitudinally placed, 6000 GVW. And no half tons had a 4L80, with a few exceptions, which I'm not 100% sure on, but I believe they would include something like the Vortec Max trucks, although I want to say they had 4L65E's, or maybe 6.2L vehicles, although I'm just guessing on that. Otherwise, your standard half ton pickup would not have had a 4L80.

Actually Not 100% correct but right for the most part, I have had a 2wd 3/4 ton that had 6 Lugs *vin stated 3/4 ton* my 94 K2500 *3/4 ton 4wd* has 6 Lugs as well. I ran the vin on my 94 says 2500. The frames on the 3/4 ton are beefier as well, I had to go look at the 88 1/2 ton I gave away to compare the 2 a couple of weeks ago. 4L60 *700r4* and 4L60E were on both 1/2 tons 5 lug *2wd* and 6 Lug *4wd* as well as 3/4tons with 6 lugs. 8 Lugs 3/4 tons along with 1 ton pickups got either a TH400 or 4L80E because of the heavier duty rear ends, more weight.

GM got confusing during 88 - 98 years because some 3/4 ton trucks had 6 lugs and semi-floating axles. Where 67 - 87 1/2 tons had either 5 or 6 lug and 3/4 ton and 1 tons had 8 lugs..

HTH,
Charlie

[TennesseeZ]

Originally Posted by 69-350

6 lug = half ton, no matter what the badges say. If it's limited to half ton engine choices, tranny choices, 8.25" IFS diff, and six lugs, it's a half ton. Only difference between that truck and a normal half ton is the fact that it has a slightly heavier leaf pack, and a 14 bolt SF. So does my 97, and it's a 1500. Somebody here on the boards used to be a GM engineer and explained it all to me, basically GM liked to put 2500 badges on trucks for awhile. Either way, if it's 6 lug, it's half ton, no matter what anybody says. If it smells, tastes, looks, and feels half ton, then it is one.

And bwood is right, by GM's naming convention, a 700R4 is a 4L60; 4 forward speeds, Longitudinally placed, 6000 GVW. And no half tons had a 4L80, with a few exceptions, which I'm not 100% sure on, but I believe they would include something like the Vortec Max trucks, although I want to say they had 4L65E's, or maybe 6.2L vehicles, although I'm just guessing on that. Otherwise, your standard half ton pickup would not have had a 4L80.

Originally Posted by dmnall

Actually Not 100% correct but right for the most part, I have had a 2wd 3/4 ton that had 6 Lugs *vin stated 3/4 ton* my 94 K2500 *3/4 ton 4wd* has 6 Lugs as well. I ran the vin on my 94 says 2500. The frames on the 3/4 ton are beefier as well, I had to go look at the 88 1/2 ton I gave away to compare the 2 a couple of weeks ago. 4L60 *700r4* and 4L60E were on both 1/2 tons 5 lug *2wd* and 6 Lug *4wd* as well as 3/4tons with 6 lugs. 8 Lugs 3/4 tons along with 1 ton pickups got either a TH400 or 4L80E because of the heavier duty rear ends, more weight.

GM got confusing during 88 - 98 years because some 3/4 ton trucks had 6 lugs and semi-floating axles. Where 67 - 87 1/2 tons had either 5 or 6 lug and 3/4 ton and 1 tons had 8 lugs..

HTH,
Charlie

Thanks guys, I had wondered, I always thought a 2500 would have 8 lugs, till I got this one. In a couple days I should be able to get it and my 89 K1500 side by side and compare frames and suspensions.

[tallkid]

just an fyi to everyone... the 4l80e wasnt available until 1995, and the th400 was an option in 2500 silverado hd and heavier models, my old boss bought a 1990 silverado 2500hd new and it had a th400.

[BigBlocksRule]

Originally Posted by tallkid

just an fyi to everyone... the 4l80e wasnt available until 1995

'fraid not. They were available in '91. They underwent changes in '95 and again later in the decade, but there are plenty of '91 454SS trucks with 'em.

[69-350]

Originally Posted by dmnall

Actually Not 100% correct but right for the most part, I have had a 2wd 3/4 ton that had 6 Lugs *vin stated 3/4 ton* my 94 K2500 *3/4 ton 4wd* has 6 Lugs as well. I ran the vin on my 94 says 2500. The frames on the 3/4 ton are beefier as well, I had to go look at the 88 1/2 ton I gave away to compare the 2 a couple of weeks ago. 4L60 *700r4* and 4L60E were on both 1/2 tons 5 lug *2wd* and 6 Lug *4wd* as well as 3/4tons with 6 lugs. 8 Lugs 3/4 tons along with 1 ton pickups got either a TH400 or 4L80E because of the heavier duty rear ends, more weight.

GM got confusing during 88 - 98 years because some 3/4 ton trucks had 6 lugs and semi-floating axles. Where 67 - 87 1/2 tons had either 5 or 6 lug and 3/4 ton and 1 tons had 8 lugs..

HTH,
Charlie

That's not true either, however. These "2500" trucks were rebadged and re-VIN'd half tons with 14 bolt SF axles (6 lug, of course) and a leaf pack rated a little above half ton GVW and a bit under 3/4 ton GVW. They are more like a 5/8th ton truck. They are 99% half ton, and 0% 3/4 ton. They have the same front suspension, same 8.25 IFS front diff, same frame, same motors and trannys, same torsion bars, same lug pattern, same hubs, same front brakes, and everything else as the half tons did. The ONLY FOUR things that were different: VIN, Badges, leaf packs, rear end (which may or may not have been available in "regular" half tons, and available in 454SS trucks in the 5 bolt pattern)

The 3/4 tons had beefier frames, bigger leaf packs, either the 14 bolt SF or FF 8 lug rear end, 9.25" IFS front diff, bigger torsion bars, slightly different front suspension, and bigger motor choices, 4L80s, etc. If I'm not mistaken, I think all 3/4 tons have 4L80E's, regardless of BBC or SBC.

I have seen 6 lug 2WD "2500s". These trucks have a narrower 14BSF, different hubs (obviously. What 2WD half ton had 6 lugs past 70?), and are the exact same as the half ton "2500s" I mentioned earlier other than not being 4WD. The only difference in one of these and a half ton 2WD is the 14B SF, the leaf packs, and the lug pattern (even I still don't know why GM made these 6 lugs)

Not to come off like an ass, but I know more about these half ton "2500s" than most other people, as I've wondered why the hell these things were, and have dug into it and done some research on them, as well as talked to a former GM engineer who worked on the bigger trucks, but kept his nose into the light duty trucks a bit.

I'm pretty sure GM built these barely beefed up half tons to market towards a niche in consumers who wanted half ton characteristics with some 3/4 ton capabilities. They simply put a heavier duty rear end in, slightly stronger leaf springs, and called 'er a day, then for some odd reason that nobody apparently knows, they decided to re-VIN these trucks and put 2500 badges on them. It reminds me of the 2500HDs and 1500HDs and all that stuff they've done recently, except these were of a slightly different nature.

Oh, and about 96/97 GM stopped doing this. My truck, a 1997 K1500, is setup the same way as the other ones. 8.25" IFS front, heavier leafs (well, it had. I put 6" 3/4 ton leaf springs in with the lift) and it also has the 14 bolt SF. Does mine say "2500" on the doors, or on the registration or title? Nope. Nowhere. Had it been made one, two, three, etc years ago, it would have.

[Colt Cobra]

so, the 94 K2500 6-Lug Extended Cab Short Bed 6.5Turbo Diesel with the 4L80 that I almost bought last year was just a "re badged" half ton?


and this
http://dallas.craigslist.org/dal/ctd/1617111434.html

[69-350]

Originally Posted by Colt Cobra

so, the 94 K2500 6-Lug Extended Cab Short Bed 6.5Turbo Diesel with the 4L80 that I almost bought last year was just a "re badged" half ton?


and this
http://dallas.craigslist.org/dal/ctd/1617111434.html

The one on Craigslist looks like an 8 lug. Maybe it's a 6 lug, but I can't see well enough in the tiny pics.

Yours basically is a rebadged half ton. Yes, you could get the diesel in half tons, in case you didn't know. All the diesels in half ton "1500s" and "2500s" had the 8.25" IFS diff and I believe they all had 4L80s. If my 97 K1500 had a diesel (which it was a possible option) then yours and mine would be identical, other than interiors of course.

[tallkid]

in reply to big blocks rule, the 4l80e was not an option in 1991 ss454s only the undestructable th400s were, mainly because at the time GM didnt make an electronic trans until 1993, and according to my lmc truck mag the 4l80 wasnt introduced until 1995.

[tallkid]

i stand corrected, the 4l80e was built in 1991, but was only an option in heavy duty models, it and the 4l60e were reworked in 1997.

[BigBlocksRule]

You'd better tell that to the thousands of 454SS drivers with 4L80E's - or do you consider them to be heavy duty?

They were redesigned in '95 (check overhaul kit dates) and again since then a couple of times.

Maybe you should into factory spec manuals or at least do an internet search, I don't think a repop supplier's catalog would be considered an accurate source of info.

[tallkid]

ok i did do some checking around and a 4l80e was an option, HOWEVER, the th400 was also an option according to a ss454 fourm. looks like we were both correct.

[69-350]

wasn't the TH400 available in 90, then 91-ups had the 4L80? I would love to have a 454SS truck. I've seen one where the dude just uses a beat up one to drive around his junkyard. Cryin shame I tell ya. Oh yeah, but I got to ride in one once! ...... in the box around the dude's junkyard anyways...

[BigBlocksRule]

Sounds about right for the years.
I can't keep my hands off an engine, so I don't really want a real 454SS, I'll leave 'em to the guys who will take care of 'em as stock. I like the later interiors, so I'm building my 454SS clone out of a '95. 4-link on the rear end, the 4L80E tranny discussed here and a pump gas 565 cubic inch tire shredder. I'm gonna put a huge honkin' sway bar on it for handling and go out and play with the Mustang boys and girls

[Bowed]

Originally Posted by tallkid

i stand corrected, the 4l80e was built in 1991, but was only an option in heavy duty models, it and the 4l60e were reworked in 1997.

Right , I have a 91 k2500 , 4x4 , 8 lug that came from the factory with a special order 4L80E .