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Anyone Here Build/Repair Auto trannis For A Living?


Scottie-GNZ

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Scottie,

If you don't have any luck on the board, try giving http://www.bowtieoverdrives.com/ a call. They specialize in GM overdrives, and from the couple of conversations I've had with them, they appear very knowlegeable and experienced. If you don't feel like going to the link, here is their phone number:760 947-5240

 

 

Tim

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I`ve been talking to this guy about 700r4`s as well as 200r4`s. he is a former powertrain engineer for GM and builds HP transmission and sells them on ebay.

Charlie2@onemain.com <Charlie2@onemain.com>

 

This is one of his auctions, http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&category=33727&item=2411007402&rd=1

 

He seems very knowledgable. :wink:

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Hey Scottie,

 

Why don't you have it looked at by the people at JW here in Rockledge. They are one of the most noted tranny builders in the country. They are also 500 yards from my house. I would love to get you over to see what I've done to the car. I have finally finished installing the full tube front chassis. It looks cool.

 

321-433-0467

Dan

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For what it is worth, here is the problem.

 

Couple of months ago the car broke down on the way to a show in Gainesville. I was convinced the problem was a brand new 9.5" 3200 stall converter. I sent the converter back and it checked out OK. I then took the tranny to a local shop and discovered the front pump was shot and had it and the shaft replaced. From a functional standpoint, the tranny performed perfect (AND STILL DOES)! but it developed a leak. The leak is at the right-front corner of the pan in the vicinity of the dipstick tube, cooler line fittings and TV cable. It looked like the pan gasket so I changed it. Same problem.

 

TMALSS, I have changed the gasket 4 times including a different pan, checked the TV cable, checked the cooler line fittings and swapped out the dipstick tube grommet and it still leaks. It only leaks under WOT and only in that spot. After dropping the tranny twice and dropping the pan 4 times laying on my back, I am at my wits end and am tired of taking ATF shampoos. Since it only leaks at WOT I am suspecting the leak is related to built up pressure forcing the fluid out whatever seal it can. There is one other change I made when I did the pump repair. I use .25" id Parker Push-Lok hoses for my tranny lines and inserted some quick-disconnects in the line bcause the cooler line fittings are difficult to get off. I am speculating that the Q-Ds might have introduced a restriction in the tranny cooler lines and is causing pressure build-up and thus the leak. That is easy enough to fix but anyone know if that theory is valid? Last resort is to pull the tranny again and have the shop recheck the pump but I really do not want to pull it. Could the leak be related to something done when the pump was replaced?

 

:evil: :evil: :evil: Folks, please do not take this the wrong way, but I am looking for feedback based on real knowledge and experience not speculation. I really want to fix this thing!! You can imagine the mess under the car and after 3 or 4 passes at the track, the entire back panel of the car is coated with fluid. Would not be surprised if I am not putting a little on the slicks too. :evil: :evil: :evil:

 

BTW, the most obvious is that the the tranny is overfilled. It is not.

 

Thanks for listening.

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Scottie,

Mybe Keith will chime in, but if not, I recommend give a REAL expert a call. Try BowtieOverdrives or someone of equal caliber in your local jurisdiction. Sounds like a question for an experienced person.

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Guest freakypainter

i know your looking for an exact fix but heres a suggestion to point you in the right direction. completely clean the underside of the trans, cooler lines, etc. put the car up on jack stands or a lift if you have access and have someone you trust put the car in drive while you are underneath the car with plenty of light and watch until fluid appears. also if you have a black light they make a flourescent dye that you can add to you trans fluid to help find leaks. also(and this is pure speculation) ive known others to change to the quick disconnect fittings on the lines only to discover they over tightened the female ends and cracked the case, that is if you have the fittings im thinking of. before you pull the tranny again I would highly reccomend the dye trick, it really does work. good luck

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Guest Rick Johnson

My car has an 86 700R4 trans. I thought I had a pan leak. I replaced pan gaskets, pans, etc and still had the leak after a hard run. (This went on for over a year - no one knew anything.) I was completely convinced that the pan gasket was the problem and surely developed some gray hair over this period.

 

I looked at an aftermarket rebuild guide for the trans that listed upgrades for this year trans. Buried in the back of the book - probably in small print - was mention of a special gasket that covered or partially covered a vent hole at the top of the oil pump gasket - I think it was the gasket between the pump and the case.

 

After using this countermeasure gasket the trans no longer leaks out the vent hose, down the side of the case (that you can't see because the trans only barely fits into the tunnel), and on to the pan.

 

Because you have just replaced the pump, I suppose it is possible that the new gasket uncovered more of the vent hole - or something along these lines. To check this out you could put a rubber line on your trans vent and route it straight down to the ground and see if your pan leak goes away.

 

I hope this helps.

 

Rick

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Thanks for the responses guys and very good ones too.

 

Freaky, I had all intentions of using the UV dye but after a pass the fluid is sprayed everywhere because there is a slight bit of turbelence under the car at 130+mph :roll::D Not sure I could tell where it originated. As for doing it in the garage, there is no way in hell I am going to put almost 550 lb/ft of torque through my driveline sitting up on jack stands :D :D

 

Rick, good suggestion. I can see the vent tube on top but not sure if it leaking there or not. It could be leaking there and running down the side. Ironically, the evidience of tranny fluid on the aluminum case quickly disappears.

 

I plan to call the bowtie guys today and regardless, eliminate the Q-Ds and put a rubber line over the vent hose and have the hose someplace where it will be evident if it is leaking from there. Unfortunately that means the tranny has to come out again....AAAAARRGGH!.

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Does your trans have a vacuum modulator? when i switched to an auto the guy that built the tranny had me put some check valves and vents in the line to the modulator. this would keep the line form seeing boost and keep it from trapping vacuum in the line and sucking the fluid out. anyway maybe your somehow leaking boost into the tranny :?:

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Guys, thanks for referral to the Bowtie guys. For the first time I feel like I have something solid to help diagnose the problem. They do not think it is the pump but a possible restriction of the flow through the cooler and cooler lines. I have .25" id lines and they recommend no smaller than 5/16". They recommend I disconnect the return line to the tranny and at idle it should flow 1.5 GPM. Since I planned to eliminate the Q-Ds, I will just go ahead and pull the cooler, have it checked for resistance, upgrade the lines to 5/16" and then check the flow rate. They also recommend doing a runout check on the flex plate to make sure it had nothing to do with the pump going out in the 1st place. Should not exceed .040.

 

Thanks again for the referral.

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Guest Rick Johnson

What is the presumed connection between a possible flow restriction in the cooler path and the leak? Where do they think the leak is actually occurring?

RJ

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JW Performance is a great shop and have been in business for many years. They built a Turbo 400 for my GTO back in 1979. The car only had 3:23 gears and that tranny would still break the tires loose going into third gear. :D

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