will it work?

Would a 700R4 out of a 2wd vehicle, such as a late 80's trans am with a 305 V8, work in my 95 K1500? I know the extension housing would need to be changed to a transfer case adapter, but is the output shaft different for a 4wd trans???

Thanks,
Aaron

i believe the output shaft on a 4x4 trans is shorter than a 2wd shaft

Yep, the output shaft would also have to be changed. Its not as easy as just removing the tailshaft housing. Output shaft is shorter, and you don't use a tailshaft housing. It should work, but then you will also have to modify the conveter lock up method since your model uses the electrnics to lock up the TCC. You will also have to add provisions for the TV cable that a non -E model needs for detent pressure. So yes it can be made to work, but I don't see that its feasible. The -E models also have later design changes that are better. If it were me, I'd stick with the E model.

I should have been more elaborate in my first post. I am converting from a 5-speed to an automatic, and am sticking to a 700R4 to avoid adding the electronics to control the 4L60E. But it looks like the output shaft would have to be changed if I used a 2wd 700R4 regardless.

yeah you got it.. output shafts gotta be switched but other then that its cake.. you wont have any reverse lights unless you figure out how to wire them in or make it so you flip a switch for them to turn on.. i have done both so as soon as i find my chiltons for your truck ill get you the wireing schematics if you want.

i think that pretty much goes for any 2wd transmission

AaronK1500 wrote:

I should have been more elaborate in my first post. I am converting from a 5-speed to an automatic, and am sticking to a 700R4 to avoid adding the electronics to control the 4L60E. But it looks like the output shaft would have to be changed if I used a 2wd 700R4 regardless.

Then there is guys like me that that prefer the 5 speed, ESPECIALLY in a 4x4. I currently am in the midst of trying to gather parts to put together a 85K10 that is factory 700r4, and I have stalled trying to collect clutch pedal linkage, bellhousing, starter, manual trans etc. What the situation on yours? Just prefering auto over manual? Another thing to consider, 95 models that were 4L60-E auto, were also PWM (Pulse Width Modulation) and the last year for TBI, so a 95 Auto trans will only interchange with itself. a 94 won't work with the ECM, and a 96 up won't work with the PCM. Now mods can be done to other transmisisons to make it work, and also have to retune your Powertrain chip. Its a real PITA. If I had a 95 that was manual trans, I'd be happier. IF you truely want auto, maybe best to purchase another used truck already with an auto, and I'd step up to 96 or newer and get the Vortec SFI (Sequelntial Fuel Injection) Where there is significant hp/torque differance above the TBI 88-95. I just wouldn't be willing to spend the bucks, time and effort on the conversion for a TBI vehicle.

I bought this truck cheap as a fixer upper, and the original trans was trashed. 2nd, 5th, and reverse were out, and it was hard to drive as it was. Add to that I've always had automatics, and that's what I'm used to in a vehicle. The reason I'm sticking with a 700R4 is for its relative simplicity, since the truck didn't originally have the controls or harness for a 4L60E. I will add a 12V signal and a switch for the TCC to operate it as needed in overdrive.

You've got the right idea then. It will be much easier to go with the manual 700r4 unit. Don't forget the TV cable and have it properly hooked up with the correct ratio on the throttle. A 700r4 will burn up in a very short time without a properly adjusted TV Cable. Try to find a 88-92 unit. They are stronger and have the better design updates than the previous years.

OK I have found some 700R4 transmissions from early 90's 4X4 S-10 Blazers. Would one of these out of an S-series blazer work in a K1500? Some ads I seen only listed S-Blazer / Astro van/ S-10 Trucks. Would they not be strong enough for a 1/2 ton full-size??

the blazer weight just as much and i dont think they did anything different to the trans so you should be good.

One other thing I thought of - They might not be listing it for use in the full size trucks because the S-series and Astro vans only had the 4.3 V6! The V8 in a full size would burn up the V6 trans. Since my truck is a V6, so this should not be an issue, right?

a trans is a trans.. they arent gonna make one weaker for a v6.. that would be pointless..

007jimmy wrote:

a trans is a trans.. they arent gonna make one weaker for a v6.. that would be pointless..

not pointless if they can make it cheaper.

thats the thing.. its not cheaper.. why would they redisn something that would work reguardless.. lol

In most case, and I am not certain of the 700r4, but example in the Turbo 350, same identical transmission in V6 and V8 models. Only differance was, in the V8 trans, each clutch pack had 1 extra clutch, and 1 extra steel, which meant the apply pistons in the drums and intermeiate piston, was just a bit shorter in the in V8 trans to make room for the additional steel and clutch. No differance in the thickness of steels either. Only differance was the apply pistons. In fact, when I bought rebuild kits, if it were a V6 vehicle, I always had an extra clutch and steel for each pack leftover. I'd assume the 700r4 would be the same way. Same transmissions, just maybe more clutches in the V8 unit is all. If it were me, even though running a V6, I'd still want to run the extra clutches and have the V8 holding strength in the clutch packs, and may add to longevity of the trans. Its as easy as using apply pistons out of a V8 trans is all. Same seals and all.

thats interesting. i've been wonderin that fer my 4.3 to 5.7 swap this summer

That's also one of the tricks to build hipo transmissions for more holding power. Is to shave down the apply pistons a bit, then use slightly thinner steel spacers and be able to add an extra clutch to each pack. Sometimes, trans shops will only do it to the low/reverse clutch pack and the intermediate clutch pack, just to be sure to have more holding power for 1st and 2nd gears for a harder launch and a nice firm solid 2nd shift. Forward clutch pack also if it were a trans running a trans brake for a mean launch off the line. Just don't be mistaken and think that is the only thing done though. That is just one of several things done. But, just saying from experience back in the days, that was the only differance I seen in V6 and V8 transmissions. And many times, I even seen v6 or i6 transmission with v8's if someone had done a motor swap, or swapped transmission from a scrap yard even. In standard performance situations, or not towing anything, usualy would not have been a noticable differance in the last 70's to late 80's since most everything was smogged and tuned down to be gutless wonders. Now days, I'd even want the v8 clutch packs with the v6's. Much more horsepower and torque with todays technology.

Well I picked up a transmission yesterday - it came out of a 1991 Astro van that supposedly had 64,000 miles. The fluid was slightly orange and didn't smell burnt, and the outer case was fairly clean with some minimal grime toward the output housing. I know I will need to change the output shaft and tail housing for the 4WD, and have read up on how to do the swap.

I have however (after the fact) found out about the "K-Case" that was used on the actual 4WD trannies. Apparently these transmissions had a heavier case around the bell housing, and were used on V8 and 4WD applications. What I got is a non K-case tranny... So my concern is will it last considering I will use 4WD maybe 2% of the time, and my truck has the same 4.3L V6 as the van

Id hazard a guess that itll hold up just fine.

i would have to say you wont have a problem.. if i used that tranny in my truck.. it wouldnt last one day at the trails so as lont as your not driving it like a complete nut on some really crazy trails then i think youll be alright..

Yeah I'm agreeing with joe on this one... You have a v6 and your not gonna be using 4wd very often your good to go... But like joe said if your like him or me for that matter then yes you want a k case... I won't run without one in my truck!



Also to make your output shaft problem alittle easier. I've seen people do it before. The difference intail shaft length is only a few inches so I know a guy who just cut the 2wd tailshaft down to the correct length with a sawzall. It's quiet unothadox but if it's 10pm on the night before the mud bogg and you are literally out of options it does work. But don't ask how I know.

Well I'm in the middle of the output shaft conversion, trying to remove the input drum. I've got the Haynes GM Transmission overhaul manual, and it says to release the band you pull this retainer pin that's under the valve body...

I really didn't want to disturb the valve body and lose all the check balls, so is there any way the release the band from the pin without removing the #$%@ valve body ???

EDIT - I was finally able to finagle the drum up away from the pin enough to get some fine needle-nose pliers in there to release the band. Sure beat removing the valve body...