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700r4 drags in reverse


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thommysgarage
User

Apr 23, 2016, 8:00 AM

Post #1 of 21 (1371 views)
700r4 drags in reverse Sign In

I have a 700r4 from a 92 Chevy truck, installed in a 57 Studebaker, with a 350 Ram Jet. I rebuilt the trans, everything looked good to me. The trans will engage reverse, but drags badly as if it is also in forward gear. It will not pull in forward, the wheels will spin if raised off the ground. I have removed the valve body and all looks good, check balls are in the right locations, no stuck valves. I have rebuilt these before, but missed something on this one. Thanks for any advise.


gsferraro
Enthusiast

Apr 23, 2016, 9:47 AM

Post #2 of 21 (1363 views)
Re: 700r4 drags in reverse Sign In

Hello,
What happens in neutral, does the car creep backward? Can you put this trans in manual one? if so, what happens when in manual one? Gary


thommysgarage
User

Apr 23, 2016, 11:59 AM

Post #3 of 21 (1351 views)
Re: 700r4 drags in reverse Sign In

The car does not move in neutral. Selecting low gear is the same as drive, wheels spin if lifted off the ground, but won't pull. I have not removed and checked the auxiliary valve body yet, is there a chance that is the problem?


gsferraro
Enthusiast

Apr 23, 2016, 2:25 PM

Post #4 of 21 (1342 views)
Re: 700r4 drags in reverse Sign In

Sounds like you may have an issue in the pump,this is also where the pressure regulator valve is located. With this trans there is nothing common to foward and reverse.
Question, did you air check the big input drum? Gary


thommysgarage
User

Apr 23, 2016, 6:10 PM

Post #5 of 21 (1335 views)
Re: 700r4 drags in reverse Sign In

No I did not do that. If the issue is in the pump, what should I look for?


gsferraro
Enthusiast

Apr 23, 2016, 6:47 PM

Post #6 of 21 (1332 views)
Re: 700r4 drags in reverse Sign In

Hello,
From the bottom pan, make sure your filter seal is tight. In the side of the pump there should be a small filter with an o-ring, this seals line pressure. Also, check the pressure regulator valve for free movement, with the pan and filter out, you can actually remove the pressure reg valve. So, you have no foward movement, in reverse does it seem to lock-up or do you have to race the engine for the car to move? Gary


thommysgarage
User

Apr 23, 2016, 7:23 PM

Post #7 of 21 (1330 views)
Re: 700r4 drags in reverse Sign In

The filter seal was good, has been removed. The car reacts when reverse is selected, but requires some throttle to move. It is not like a loose converter, but more like the brakes are being held.


gsferraro
Enthusiast

Apr 24, 2016, 6:28 AM

Post #8 of 21 (1315 views)
Re: 700r4 drags in reverse Sign In

 Do you by chance have a pressure gauge? sure like to see whats going on inside this unit. since it seems like it binding in reverse and no foward, you may have to get back inside this trans, i would check the pump but also look closely at the input rings and stator sealing rings, you will also have to air check the input drum, to make sure there are no cross leaks. What year is the transmission? you mentioned aux valvebody, this has the tube going into the pump?


thommysgarage
User

Apr 24, 2016, 9:11 AM

Post #9 of 21 (1308 views)
Re: 700r4 drags in reverse Sign In

The trans is a 92, I did check the numbers. It has the auxiliary valve body and a tube connected to the pump. A fellow in the shop suggested it might be the low roller clutch. Does that sound plausible?


thommysgarage
User

Apr 24, 2016, 9:13 AM

Post #10 of 21 (1307 views)
Re: 700r4 drags in reverse Sign In

Sorry, forgot to tell you I don't have pressure gauge. I could borrow one if needed.


gsferraro
Enthusiast

Apr 24, 2016, 10:36 AM

Post #11 of 21 (1304 views)
Re: 700r4 drags in reverse Sign In

If it was the low roller clutch, the car would pull off in low gear. you mentioned check balls, with aux valvebody, you should have 2 check balls in the valvebody(not including the one in the aux valvebody) Gary


thommysgarage
User

Apr 24, 2016, 12:18 PM

Post #12 of 21 (1303 views)
Re: 700r4 drags in reverse Sign In

Yes there are two check balls in the valve body.


gsferraro
Enthusiast

Apr 24, 2016, 1:02 PM

Post #13 of 21 (1298 views)
Re: 700r4 drags in reverse Sign In

Ok, very good, i can also only assume that you have the correct valvebody gaskets in this trans, if so, maybe before it gets pulled out, take a pressure reading to see whats going on. I would like k to know what the base line pressure is in this unit. Drive at an idle should be around 65psi. Gary


thommysgarage
User

Apr 24, 2016, 2:13 PM

Post #14 of 21 (1296 views)
Re: 700r4 drags in reverse Sign In

OK, I will put the valve body back on and put a gauge on it. Do you know what size fitting it is?


gsferraro
Enthusiast

Apr 24, 2016, 5:11 PM

Post #15 of 21 (1290 views)
Re: 700r4 drags in reverse Sign In

should be standard 1/8 pipe. the threads on the gauge should go right in. Gary


thommysgarage
User

Apr 25, 2016, 9:17 AM

Post #16 of 21 (1278 views)
Re: 700r4 drags in reverse Sign In

Checked the line pressure, it is high. It was 145 in drive and in park, pegged my 160 psi gauge in reverse. Is this definitely a pump problem, like a pressure valve stuck? I did notice that the tv lever does not contact the end of the valve when reinstalling the valve body, it has to move to probably half throttle to make contact. Does that seem right? I do have the cable adjusted for full travel at full throttle.


gsferraro
Enthusiast

Apr 25, 2016, 3:18 PM

Post #17 of 21 (1264 views)
Re: 700r4 drags in reverse Sign In

Hello,
Very Strange, with 145psi in drive, this thing should slam into gear. Yes pressure is way too high. With pressure that high, possible blown out seal or snapring. I would look at the pressure reg valve in the pump to see if its stuck closed, then you will most likely have to get back into this trans, but i would air check the input drum before disassembly. Being the fact that this does not move in low, the problem may be in the foward clutch, which is the middle clutch pack on the input drum. Gary


thommysgarage
User

Apr 25, 2016, 3:32 PM

Post #18 of 21 (1262 views)
Re: 700r4 drags in reverse Sign In

Thanks for your help. I will pull it out tomorrow and start checking everything. I did notice that the fluid that I drained out was very dirty to come out of a fresh trans with just a few minutes of run time on it. I think it may have been contaminated from a new trans cooler or torque converter, may be the root cause of my problem. Thanks again, Brad


gsferraro
Enthusiast

Apr 25, 2016, 4:12 PM

Post #19 of 21 (1259 views)
Re: 700r4 drags in reverse Sign In

When you pull that out, if you have any questions about air checking the drum or anything, while its apart let me know. I will answer as soon as i can, my shop is packed with transmission work. Gary


thommysgarage
User

Apr 27, 2016, 5:34 AM

Post #20 of 21 (1241 views)
Re: 700r4 drags in reverse Sign In

It may be a couple of weeks before I get in to it. I have lots to do as well. I will post what I find when I get back to it. Thanks for your help, Brad


gsferraro
Enthusiast

Apr 27, 2016, 3:11 PM

Post #21 of 21 (1224 views)
Re: 700r4 drags in reverse Sign In

 Your welcome, let me know. Gary






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