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Transmission help needed

90RedBurb

90RedBurb

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Hey guys haven’t been on in awhile but I’m looking for some help from someone more knowledgeable than myself about my auto-magic transmission( 700r4 1990 suburban). Long story short it had been parked for awhile and I didn’t realize the pan gasket was leaking and I drove it low on fluid. I made 2 runs to the dump about 10 miles from my house and on the second trip home I stopped at the gas station 1 mile from my house. When I left the gas station it acted like it had no first or was slipping. I limped it home and parked it. When i pulled in my driveway on a slight incline it had all the gears again. Checked the fluid and it was low, kind of dark and smelled burnt. I dropped the pan and didn’t see anything out of the ordinary put a new filter and gasket on and refilled it. I also had a new tci corvette servo laying around and tossed it in at the same time( in hindsight probably bad timing on my part) it now has all gears with no slipping and shifts good again however it doesn’t seem to want to stay locked up on the highway. Could I have damaged something with the torque converter lockup by running it low on fluid or could it possibly be something to do with the corvette servo install? Any help is appreciated as im not sure where to begin with my repair efforts. Thanks
 
Not sure about damaging the tcc by being low on fluid.

First thing is check break switch adjustment.
 
Thanks i will look into that when i am home next. working out of town right now and wont be home for another week but trying to develop a plan to try and repair it in advance. only have 1 day off a week so trying to be prepared. Does installing the corvette servo require readjustment of the TV cable? Shifts seemed good and at the speeds where i have seen in info ive found before. Only drove about 2 miles after this work was completed.
 
90RedBurb said:
Thanks i will look into that when i am home next. working out of town right now and wont be home for another week but trying to develop a plan to try and repair it in advance. only have 1 day off a week so trying to be prepared. Does installing the corvette servo require readjustment of the TV cable? Shifts seemed good and at the speeds where i have seen in info ive found before. Only drove about 2 miles after this work was completed.
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It would be super easy to put the other servo back in and see what it does
 
Yes and I still have the old servo so I would only need an extra blue oring on hand in case I couldn’t get the one out in one piece. I just wasn’t sure if that servo would affect the lockup or not. Really wish I wouldn’t have changed it out when I did. On a side note the servo I removed looked identical to the new one I put in and this transmission was rebuilt by the previous owner probably 8 or so years ago. I have owned it 5 or so years.
 
From what I know the Corvette servo gives faster and firmer shift with more pressure, therefore creating less heat. I don’t think it has anything to do with OD. But let’s hear from the expert.
 
The servo holds higher pressure for applying and holding bands, and accumulator for 3rd. Nothing for tcc.
Do not adjust the TV cable if it was correct before.
 
Ok thanks guys. Yeah I haven’t touched the cable since i went through the throttle body a couple years ago. This is leading me to believe that it may be wounded after the low fluid event which is unfortunate but we will see what others say.
 
Check the TV cable, should be as tight as it can possibly be at wide open throttle. The servo did not have anything to do with the converter and limping home on low fluid could not affect the torque converter clutch since it probably wasn't even applied at lower speeds. If you still have a solid third and 4th gear you should have a good converter clutch.
 
Thank you guys for the responses. I will check the TV cable as well as the brake switch when i am home this next weekend and report back with my findings. The little bit i drove it after changing the fluid and servo it seemed to be working really well and had nice shifts and all the gears worked great until the goofy lockup situation was noticed.
 
Well I got home late last night and it was dark so I went out this morning and there is a small wet spot under the transmission so the new gasket I put in apparently didn’t seal so I’m going to order a new pan and lube locker gasket because this leak has got me irritated. I have a lot to do and about 5 hours to get it done before I head back out of town for the week so the suburban will have to wait until next Sunday.
 
90RedBurb said:
Well I got home late last night and it was dark so I went out this morning and there is a small wet spot under the transmission so the new gasket I put in apparently didn’t seal so I’m going to order a new pan and lube locker gasket because this leak has got me irritated. I have a lot to do and about 5 hours to get it done before I head back out of town for the week so the suburban will have to wait until next Sunday.
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Make sure the leak is from the pan and not the dipstick tube or the TV cable seal.
I had that happen to me so check both locations
 
I will look into that as well. It appears to be leaking from the passenger rear corner which is where it was leaking from before but it’s possible it’s running there from another location
 
Does anyone have a recommendation on a good quality aluminum transmission pan that has a drain plug and fits the 700r?
 
I have a question that maybe I should start a new thread for but I’ll try here first. I just found a guy that has a complete swap (minus transfer case) sm465 setup. It has transmission, bellhousing, pedal assembly, hydraulic master and slave cylinder, flywheel and clutch. Will my 241 bolt to this or does it require a different shaft? Also how does length compare? New driveshafts needed? Setup came from 87 v30 big block so I would need different flywheel. Thanks in advance
 
Your t-case may have a 27 spline input.
The setup from the v30 may be a 32 spline.
You would need to confirm. It is very common to swap a 32 spline input into your existing t-case. I am assuming its either a np208 or 241.
 
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