2 700r4's one is AUX valve body and the other is not......?

[Burb restorer]

Greetings to all. Hopefully, I can explain this without too much confusion. I have a 1987 Chevy Suburban, V10 4WD. The 700r4 in it does NOT have the aux valve body (NOT a K case). The code is 7TXM-Y-00525758-276B. I have another 700r4 and it DOES have the aux valve body. The code for that one is 0KRM-135H. The original trans in the truck has the three wires coming into the left hand side of the case going to the valve body and there are several pressure switches. BUT, the OTHER trans I want to build (IS a K case) and install in the Suburban has NO wires at all attached to the connector, no wires in the trans, only ONE pressure switch. Now, I am confused. I know this trans is shifted with the help of the governor but what about the torque converter clutch? What's the correct thing I need to do to be able to run this trans I want to build? THANKS!!

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[yevgenievich]

Install a lock up harness and solenoid. Usually sold as a lock up kit. Or transfer from other trans. Usual operation is to have 4th gear pressure switch enable lockup ability and then vacuum controlled switch would actually engage lockup if in 4th gear

 

[Burb restorer]

Hey THANKS! So, I guess the guy who had this Aux valve body trans in his 86 C10 must not have had any TCC operation. I wonder if the torque converter that came with it (NO, I won't use it, I will buy a new one) even has the torque converter clutch in it. MANY THANKS AGAIN!!! Oh, any suggestions on the BEST lock up kit to buy? THANKS!!!

 

[mmerlinn]

You have me confused.

I have owned several 7TXM 700-R4 transmissions and every one of them were auxiliary, were K cases drilled for the aluminum dust cover, and were 4x4s.

That said, 1987s are a weird bird that many rebuilders do not want to rebuild. Core value for a 1987 is HALF of any other year from late 1984 through end of production in 1993.

 

[Burb restorer]

Well, hate to tell you but the 7TXM 700r4 transmission that is currently IN the truck has pressure plugs, NO wavy parting line on the right hand side of the case and NO aux valve body unit with the tube attached. Not there. AND there is NO "K" on the case either. But, there are 6 bolt holes for the aluminum flywheel cover. So, I wonder how this happened?

 

[Ricko1966]

No kit needed for tcc lockup. A plain old four wire relay and a fuse the 4th gear switch is already in the transmission It goes into 4th gear closes the relay and powers up the tcc lockup. I think it it is switched power to 30 and 85. 86 to 4th gear switch 87 to tcc solenoid other side of solenoid to ground fuse your power lead.Throw a toggle switch on the power if you want the option of running unlocked. The relay is so your 4th gear switch never sees any substantial current.

 

[Burb restorer]

Check out this picture of the trans I am about to rebuild. The TCC solenoid isn't there. I guess I was pretty tired and didn't even see this since I just started on it this afternoon.

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[Ricko1966]

No kit needed for tcc lockup. A plain old four wire relay and a fuse the 4th gear switch is already in the transmission It goes into 4th gear closes the relay and powers up the tcc lockup. I think it it is switched power to 30 and 85. 86 to 4th gear switch 87 to tcc solenoid other side of solenoid to ground fuse your power lead.Throw a toggle switch on the power if you want the option of running unlocked. The relay is so your 4th gear switch never sees any substantial current.

Check out this picture of the trans I am about to rebuild. The TCC solenoid isn't there. I guess I was pretty tired and didn't even see this since I just started on it this afternoon.

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Wow.I'll stfu now. Been to 3 state fairs and 2 fancy goat f#€k$ and never seen that.

 

[mmerlinn]

Well, hate to tell you but the 7TXM 700r4 transmission that is currently IN the truck has pressure plugs, NO wavy parting line on the right hand side of the case and NO aux valve body unit with the tube attached. Not there. AND there is NO "K" on the case either. But, there are 6 bolt holes for the aluminum flywheel cover. So, I wonder how this happened?

Like I said, 1987 is a WEIRD BIRD, so anything is possible in that year. I cannot argue with what you have in your truck, all I can do is present what I have seen in the hundreds of 700s I have owned since 1984 when they first came out.

MOST, but not all, auxiliary cases have the St Louis Arch on them. I have never seen it on 1992/1993 700s. When I see 700s without the St Louis Arch, I always check the codes. I have bought a lot of cheap auxiliary 700s that others thought were non-auxiliary because there was no arch.

Further, most, but not all, K cases have a K on them. The only sure way to tell a K case from a C case is the ability to be drilled for an aluminum dust cover. C cases cannot be drilled for K trucks needing an aluminum dust cover. K cases are sometimes drilled for K trucks (alum dust cover) and sometimes drilled for C trucks (steel/plastic dust covers).

All in all, GM really is screwing with our brains when it comes to 700s.