Good afternoon all. I have a 57 fairlane with a t86 o/d that I rebuilt myself about 40 miles ago. the skinny is it pops out of second when engine braking. ALSO did this with the old transmission in it too. The rebuilt trans has new syncros and bearings, and if memory serves me, a couple of new gears as well. this is my first column shift car so what might be obvious to some
If the linkage is adjusted properly and the internals are new, the problem may be bell housing miss-alignment. Basically the transmission input shaft isn't in perfect alignment with the crankshaft center line. This puts the input shaft in a bind and causes the sychronizer ring to walk off the drive dogs. It is almost alway causes a popping out of second problem. Most older service manuals (50's - 60's) show how to check and adjust the bell housing.
A common cause of jumping out of gear, is wear on the sides of the synchro teeth on the gear, and where this contacts the inside of the synchro sleeve.
Yep, adjust the linkage first to make sure it's going fully into gear. And check bellhousing alignment. With that said, the '50s/'60s era BW manuals were somewhat known for this. The T10 was the worst offender. The brass blocker rings are only there for shifting, they don't help hold it in gear. If the syncro teeth on the gear itself and/or the slider is worn enough (rounded ends/sides) this is the result. BW (or was it Richmond? I can't remember...) did fix the T10 eventually by backcutting the teeth on the gear and a matching cut in the slider to 'lock' them together under load, but that refinement didn't filter down to the T85/T86. That version was the 'Super' T10. If that's what you find, the only cure is a new/better used gear and/or slider, preferably both.
Thanks for the responses guys. I’m gong to start with the the bell housing check. With the gear selector in 2nd gear I cannot move the shift linkage any further in that direction telling me it’s fully seated. I wish I could remember what I purchased to put in the trans when I rebuilt it. I know it was bearings and synchros. And I almost want to say the sliders. ♂️ I had the engine out as well as the trans rebuilt so probably should play it safe and make sure the bellhousing is good. Watched a few videos and doesn’t look like a hard procedure!
There is supposed to be one or maybe 2 thrust washers on the cluster gear and any slop will help it to jump out of gear.
I wouldn't assume that the synchro is fully seated just because the gear selector won't go any further. I would put it in gear and get under it to pull the linkage and make sure that the gear selected is fully seated. If the problem was happening before the rebuild I would suspect that you may have not replaced that gear/slider set. As others have said here, popping out of gear can be caused by: - worn synchro teeth on the gear/slider - engine/trans not concentric - shifter/linkage issues - loose counter shaft/main shaft (excessive clearance) As far as checking runout, I checked it on a new Tremec small block T5 bellhousing and had to install and position .007" dowels to get the runout down to .0015 (from .006"). I use a camera to capture each check and went to work. Good luck!
Did you check the clearance between the input and output shaft ?? All the above are good suggestions, The sliders and teeth on the gears have always been round a bit on most of the B/W trans I have rebuilt Had a T-85 R-11 O/D that that started popping out of second The rear bearing was worn and there was a lot of slack between then input and output shafts The gear oil was leaking out of the rear section and got too low to oil the bearing Ricky.
Just to clarify further. This is not the original trans. The trans I took out popped out of gear AS WELL as the transmission I rebuilt and replaced it with. The first trans was a 48-54 case with 57 tail shaft. The new trans is a complete 57 t56 with o/d. I did get under the car tonight and verified the arm on the trans was fully engaged when the gear selector is placed into 2nd. The linkage does make slight contact with each other in this position but it’s pretty light and even with the 1/r linkage removed, it doesn’t change the 2/3 engagement at all. Since this is a new to the car trans (and not the original engine either) I’m going to go ahead with the bell housing alignment just to make sure I have a good foundation to work with. It does have some odd vibrations that come and go with throttle (sometimes) that I think is pinion angle and sagging rear springs… ruling out the bell housing alignment will be one less potential cause of that too.
Well guys think I found the problem. The fork for 2/3 allows for far better engagement between the sleeve and the input shaft then it does between the sleeve and second gear. Appears the cause is slop between the fork and the sleeve, however I don’t think either part is worn, I question if one of those is just wrong. I dug though my parts bin of a newer t86 (used to many different parts to be a perfect parts donor) and grabbed the fork out of that and it is much wider and shaped ever so different. Looks like I’ll be tearing it all down to replace the fork .
Yup. If that fork wasn't moving the slider into full engagement then there might be some additional wear. ETA: I just realized that pic is from your trans. You got another problem to deal with there. Ouch...
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