NEED TRANS HELP ON A C6

[chief1ff123]

I have 89 f250 that the trans (c6) is slipping bad. Last summer i changed the fluids and filter. Added trans helper. I think it was by lucus. It hepled for awhile then problem is back. Also it heats up real bad. Can't keep your feet on the floor board. But my brother gave me another truck (f250 diesel 92 i think) My plan was to take out the trans of the spare truck and install it into my 89 f250. The 91 is not a 4x4 but the 89 is. I've been told this would not mount to the transfer case. can someone help me with what i can do? Thanks for your time.

 

[NJKen]

You have a few things going against you here. First off 2 wheel drive to 4 wheel drive is about as expensive as a rebuild when you are done. The second problem is the 91 should have an E4OD. If you did convert it to 4x4 you would need to shorten your rear driveshaft, lengthen the fron driveshaft, and swap in the computer and all related wiring to controll the E4OD.
Now, the C6 is one tough trans. You need to google search "C6 Band Adjustment" and find a writup on that procedure. The C^ is one of the last automatics built with extenally adjustable bands. That may not totaly fix it but it may buy you time. I have adjusted them in the past and it feels like a new trans sometimes.
Best of Luck
Ken

 

[chief1ff123]

i do have all the wiring with the old truck. the driveshaft shouldn't be that bad. how much do you think the rebuild is gonna be?

 

[dieselsalley]

hello you will have to change the output shaft on 2 wheel drive trans to fit onto transfer case on 4wd the spline lenght is longer on 2wd and you can not cut there is not enough spline . be sure to measure youre extension housing there are 3 different lenght shafts &housings by the way the the extension housing on the c6 will not fit on to the aod trans so ou will also have to change that to and may have to make new mount holes in crossmember the studs are wider apart hopes this helps

 

[OLDBULL8]

You say the transmission is running very hot. This is normally caused by overfilling the transmissiom fluid, it's very important not to overfill a C6. Check the fluid level with the transmission HOT in PARK and Engine running. If it's overfilled you will have to drain some out.
To adjust the intermediate band, there is a screw on the side with a locknut on it, loosen the locknut and with a torque wrench tighten the screw to exactly 10 Ft Lbs., then backoff the screw EXACTLY 1-1/2 turns, hold the screw so as not to turn and tighten the locknut to 35-40 Ft.Lbs. They recommend that you throw away the old locknut and install a new one.
If you have had shifting problems, then the the VSV (Vacuum Servo Valve) has to be adjusted, that is mounted on the Injector Pump. It's quite a procedure. If you have this, post in this thread, and I will copy the procedure and post it. You have to have a vacuum pump and vacuum gauge and a gage block 0.515 thick to do that.

The E4OD transmission will not bolt up where the C6 came off, bell housings are different. Good Luck.

Looked at your truck, if you don't have an auxilliary trans. cooler, hauling that Camper you really should have one, maybe that is why you are running hot.

 

[gte718p]

I have a c6 in an 88 that is down so I need the procedure. I think I'm toast though. The band adjustment screw was loose. I tried to set it correctly but it spun all the way into the hole before it got to ten foot pounds. In fact it free spun all the way in. I can go first to third, but I can't get second. When I have my trailer on I can get third, but it will not hold it drops right back to first.

 

[NJKen]

I have a c6 in an 88 that is down so I need the procedure. I think I'm toast though. The band adjustment screw was loose. I tried to set it correctly but it spun all the way into the hole before it got to ten foot pounds. In fact it free spun all the way in. I can go first to third, but I can't get second. When I have my trailer on I can get third, but it will not hold it drops right back to first.

The band is either smoked or broken. Time for a trans now.

So, whatever happened to the original poster here? Did you get it running? Change it out? I hope your not still sitting on the side of the road somewhere.
Ken

 

[Smokey73]

I have 89 f250 that the trans (c6) is slipping bad. Last summer i changed the fluids and filter. Added trans helper. I think it was by lucus. It hepled for awhile then problem is back. Also it heats up real bad. Can't keep your feet on the floor board. But my brother gave me another truck (f250 diesel 92 i think) My plan was to take out the trans of the spare truck and install it into my 89 f250. The 91 is not a 4x4 but the 89 is. I've been told this would not mount to the transfer case. can someone help me with what i can do? Thanks for your time.

I'm not one hundred percent certain, but I think the t-case from the C-6 will bolt up to the E40D, T-19 even the ZF5. You'll also have to change out all the electronics that go with the E40D. There's another thread on here where someone just recently swap in a ZF for a C6, if I recall, with little troubles.

 

[NJKen]

As long as its a trans that came in the truck (as listed above) at some point the T-case will fit just fine. If it is a weird trans you may need an adaptor.
Ken