Transmission Issue

[MRGEORGE077]

I’m still sorting out the Shelby American 289 slab side that I took delivery on several months ago. The current issue is as follows:

Up until two weeks ago, I had only driven the car short distances but on this occasion, I decided to drive the car for an extended period of time, that day it was about 101° during the drive the engine never exceeded 195° and the oil temperature never got above 185.

The Cobra has installed a Borg Warner T10 transmission. After about 1 1/2 hours driving at highway speed I went to down shift into third to stop at a red light. When I pulled it out of fourth the transmission totally locked up, and I could not get it into any gear. I pulled over to the side of the road and after a sitting for a short-period time I got it back into first gear from that point I ran through the gears to be fourth, but the very next time I went to down shift the same problem happened. Once again, after pulling off the road then sitting for a few minutes I could get into first ran to fourth and keep it there until I reached home.

The next morning the transmission was working fine. I drove it to a repair shop where I was having some heat retardant insulation installed. I told the mechanic about the problem and we all kind of felt it was an external heating problem, hydraulic fluid boiling, and that’s what caused the transmission, or clutch, to seize up. We hope that the installation, we were installing, would fix it.

A week later when driving the car to the trim shop, which was only about 15 miles, we experienced no problems. The same is true when I went to pick the car up, yesterday, from the trim shop to drive it back to the mechanic, there was no issue. After visiting with the mechanic for about an hour and a half, I started to drive the car home but only get half a mile when the transmission totally froze this time when I pulled it off to the side of the road and set for a while it would only go into reverse, first and second but third and fourth were totally locked out. We trailer it back to the shop where it now sits, maybe after sitting over the weekend it will work again.

Does anybody have any ideas what possible might be wrong with this transmission?

[ERA Chas]

This is a total reach 'cause I never had a T-10. But being an aluminum cased trans, the easiest thing I'd do is check the trans mount at the tailshaft. Misalignment could cause flexing when hot and bind. Loosen the trans to mount bolts and the mount to frame bolts and see if it shifts.

[Rick Parker]

I have a T10 in my car and it has worked well, especially considering I paid $175 for it originally. Most of the T10s were Iron cased, very few of the Ford applications used Aluminum. T10's were most notably used in Falcons, some early full size Fords, and early Mustangs, applications dictated different length tailshafts. The shifting mechanisms occasionally have some wear in them that make shifting difficult. Check the rubber bushings that hold the shifter to what is refered to as the control box. These were NOT used on the OEM Cobra application but were later added to eliminate vibration from being transmitted through the handle and creating a "BUZZ" while at speed. If the bushings are bad the handle will move from side to side and be sloppy, making actual gear selection difficult. Next have the control box that the handle attaches to looked at. If the large 3/4" shaft is worn, it too will create issues when selecting different gears. Next check & or adjust the fork shift rod mechanism. Put the shifter in neutral and insert an 1/8" diameter pin, drill bit, through the hole in the side of the control box and through each arm in the control box, remove the shift boot or do this from under the car. This assure you the shift lever itself is in neutral before any further adjustments. Next loosen the nuts that attach the shift rods to the levers on the contol box, move each lever on the transmission to it's respective location for neutral which is dictated by detents in the side case and then tighten the nut securely. Do this (or have this done) for all 3 shift rods. Be sure also there is no interferance with the shifting mechanism and transmission tunnel housing. Use 90 weight gear oil in the transmission not one of the newer lightweight oils that are commonly used in the newere transmissions. If this does not resolve your problems, the gearbox will need to be opened up, there may be too much end play within the gear clusters. Due to their age, and who is doing the repair, used parts are chosen in the rebuilding process and this often causes problems, due to the wear on the parts used. Most notably the syncro hubs staying locked on the chosen gear because the "Points" that are ground on the gear become rounded off by improper gear selection, speed shifting or "Jambing gears. This allows the transmission to "Pop out of a gear" either while slowing down or sometimes while accelerating. Once corrected they shift smoothly and are trouble free. All this assumes the clutch itself is releasing fully when the pedal is depressed.

[IMG][/IMG]

[ERA Chas]

Originally Posted by Rick Parker

Most of the T10s were Iron cased, very few of the Ford applications used Aluminum.

Nice tutorial and thanks for the correction Rick. Most of the 'Vette guys I raced in the late '60's had ally T-10's. I had a WR Muncie.

[Rick Parker]

oops!

[MRGEORGE077]

Thanks for everyone's input it's very much appreciated. And that we have installed extensive heat shielding I don't believe it's the hydraulic system getting hot but more likely some kind of miss alignment.


I also said received the following information from the company that provided the transmission and clutch:


George
This certainly sounds like a problem with the hydraulic clutch system as when it cools you were able to shift the transmission. The clutch plate isn’t being compressed enough to allow smooth shifting. Im guessing the exhaust is too close to the clutch master or the slave cylinder and is boiling the fluid. . Ive experienced this problem with race cars and heat shields are needed to keep it from coming back. What has probably happened is when the clutch isn’t properly working you are forcing the synchros and the small detents have possibly been broken. Ive repaired a few with same symptons.

I would try to do a few things before pulling it out to make sure. After installing some heat shielding on the clutch master, slave or on the closest pipe. Make darn sure the shifter is aligned properly. Make sure its in neutral and see if the alignment tool fits snugly in the control box and thru all the rods. If it doesn’t go in, loosen the nuts on the control box lever , insert the tool and tighten the nuts.

I would also check the clutch plate adjustment , if the clutch pedal doesn’t compress it enough that’s another red flag. One of the other things we do on our race cars and we don’t normally do on a street engine . On a street car we normally don’t do anything about checking the bellhousing alignment as they are usually factory parts. These have the factory original bellhousing and shouldn’t be a problem . I don’t know if Norwest dial indicates the bellhousing but it’s a consideration if you end up pulling out the transmission to make sure the alignment is totally square. Ive only had problems with aftermarket bellhousings but never a ford factory unit.

Please keep me posted if this alleviates the problem, if it doesn’t then Im guessing you’ve broken one of the synchros and the box has to come apart

[Rick Parker]

One last thing: Inevitably the fluid displacment ratios between the M/C and slave must be right. so be sure the diameters of the respective parts are as specified and the correct length clutch release lever is being used.

[patrickt]

Originally Posted by MRGEORGE077

Does anybody have any ideas what possible might be wrong with this transmission?

No. But if it was me, I would zip tie my camera lens so it's pointing right at the slave/fork, get so I knew exactly how it "normally" looked, and then drive around until the problem re-appeared. Then turn the monitor on and see exactly what the slave/fork looks like now. Record it as well -- that might answer the question. Here's the tool I would use (since I just bought it): New Cool Tool - DeWalt DC410 Inspection Camera - Quick Review with Pics and Video

[MRGEORGE077]

Originally Posted by patrickt

No. But if it was me, I would zip tie my camera lens so it's pointing right at the slave/fork, get so I knew exactly how it "normally" looked, and then drive around until the problem re-appeared. Then turn the monitor on and see exactly what the slave/fork looks like now. Record it as well -- that might answer the question. Here's the tool I would use (since I just bought it): New Cool Tool - DeWalt DC410 Inspection Camera - Quick Review with Pics and Video

WOW!! now that is cool and also a great ideal.