85 C6 questions

[IHdieselfan]

I've been work on my friends 85 with a c6 we put the motor back in. he drove approx. 200 miles trans good a first a little soft shifting but nothing that couldn't be fixed with a little vrv adjust. now it went to very soft shift and slipping nothing i did to the vacuum made a difference. brought the the truck to the shop. dumped some seafoam trans tune in there and run it and then dropped the pan found orange rtv a bolt out of the valve body and some nasty fluid and trash in the filter. drained the TC installed new filter filled with John deere HYGARD. now forward works like it did before but reverse is slipping when you give it some throttle. I adjusted the intermediate band. and played with the vacuum and no change. tapped a gauge in to the pressure port in front of the shifter. at idle in park i had 50 psi. in forward 60 psi. in reverse 80 psi. all those pressures seem low to me. is there a way to adjust trans pressure. I have rebuilt allisons and john deere 15 speed powershifts. I'm guessing that a c6 is about the same.

 

[77f250diesel]

You could try removing and cleaning out valve body.
If you found that much junk in the pan there's a good chance it's also in the vb.

C6 is easy to rebuild if it comes to that just pick up the ATSG manual.
I'd try the vb first, keep track of where everything goes.

Dennis

 

[OLDBULL8]

On a C6 the shift linkage is critical that it be adjusted correctly so that it pops into the detents inside the tranny. The pressures should be checked with the tranny at operateing temp of 160 to 170 degrees. Make sure the vacuum supply hose is plugged into the top port of the VRV, bottom hose/line in the bottom port, I've seen them get switched causeing shift problems.

 

[HammerDown]

On a C6 the shift linkage is critical that it be adjusted correctly so that it pops into the detents inside the tranny. The pressures should be checked with the tranny at operateing temp of 160 to 170 degrees. Make sure the vacuum supply hose is plugged into the top port of the VRV, bottom hose/line in the bottom port, I've seen them get switched causeing shift problems.

Could someone post the proper adjustment procedure?

 

[IHdieselfan]

vacuum connection has the little connector that keeps it hooked up correctly. and trans was at operating temp. checked it with temp gun never went above 150F. now the shift linkage is hard to know what gear your in.