I have a BW T85 (non-overdrive). It is originally from a 1957 GMC pickup. It is now in my 1927 Ford Model T hot rod behind the original 347 Pontiac V8. I am having trouble with changing gear and getting it from 1st to 2nd. Occasionally it jams between gears. It clearly needs a rebuild unless anyone can advise me otherwise. I was hoping it was clutch adjustment but doesn't seem to be the case. I have adjusted it up so that it slips in 3rd gear and it still baulks on 1st to 2nd upshift. I know that these boxes don't like to change down from 2nd to 1st on the move and I also do the trick of slipping it into 3rd before going into first. I do something similar with my 2CV. I'm resigned to a rebuild but having trouble tracking down a full rebuild kit to include synchro rings, bearings and gaskets. Can anyone advise me of a supplier? I believe a T10 kit can be used.
I'd take it apart and inspect things carefully before ordering parts, because you need to know which parts to get. I would not assume that bearings, gaskets, and synchro rings would fix it. Looking in the 59 Chevy parts book, there are many interchangeable parts between the T10 and T85, but there are some that are not.
Some pickups, including Studebaker V8s, used a version known as T89. These have a lower first and second gear ratio. They can be identified by the straight cut low-reverse sliding gear and the straight splines on the shaft it slides on. The straight first gear supposedly made it easier to downshift from second to first while rolling; important in a non-synchro low truck with a load on board. The downside is the straight splines do not shift as easily going up from first to second, especially after they get some wear. The best fixes for this are a good floor shift conversion and Redline MTL lubricant. jack vines
The jamming between gears sounds more like a linkage problem than internal to the trans. The other issues sound like synchronizers and/or bearings. But like Squirrel said, one needs to have it on the bench before one can tell for sure.
Can you get the casting numbers off the trans ?? ( Occasionally it jams between gears ) do you get under the car and un jam them or ?? Ricky.
Having owned T-85’s I’d be taking a close look at the linkage first. No slop in a syncro loc. Seems to me there’s some linkage between the R-1 and 2-3 shift arms on those. Combination of the shifter and that just a little off could do that. That’s a pretty fuzzy memory though.
There's something BW call rooster combs that prevent the shifter arms from shifting into two gears at once. I can have the side panel off with the box in the car to check that. I can also set the SynchroLoc up again and see if it needs any more adjustments. In gear and moving the box is silent and does not jump out of gear or cause any problems. It's neutral to 1st and reverse and 1st to 2nd where I'm having problems. I had no rods for the SynchroLoc (because I'm in the UK and this stuff is hard to find) so made my own from 1/2" aluminium bar stock and M8 RT rose joints. There is no slop whatsoever in those so I will see if I can introduce a bit of wiggle room.
“Rooster Combs”. That’s a term I haven’t heard, but described the function I was talking about. One way or another, it’s all got to line up or you’ll get a problem similar to yours. I don’t know if slack in the shifter, repair of the Combs, or what is the solution. But if so, it’s better than pulling a T-85. They’ve gotten a lot heavier the last few years. The modern oil must weigh more, it can’t be old age.
I will give all that a try. Would like to avoid having the gearbox out and on the bench if possible. Strangely it shifts very easily when the engine is stopped. I hear you about the weight. I am 65 and I can still lift the weight I could when I was 30 - but only once and then I feel it all day.
If the transmission sifts fine when the engine is off but not when the engine is running maybe the transmission input shaft is hanging up in the pilot bearing, it also could be the clutch disk sticking on the input shaft (so it continues to rub against the flywheel or pressure plate with the clutch depressed), it also could be due to not enough space between the flywheel and pressure plate with the clutch depressed.
I will get a feeler gauge in there and check plate to flywheel clearance. Not sure how to check the other stuff - maybe put it on axle stands and turn the engine over by hand with the clutch depressed. The gearbox and engine are original to each other - from the same 57 GMC truck. Clutch is new.
Sometimes new clutches have problems, but it's less common now that most of them aren't rebuilt. But definitely check for full release as you just mentioned....
as long as there's enough room to remove the side cover...the forks stick out of it a ways, perhaps 3 inches
Tell us a little more about the hanging up and how you correct it when it happens. That might provide a clue as to the root cause, external to trans or internal. FYI, if you want to remove the side cover in car and don't have a lot of room, you can remove the mounting bolts (trans to clutch housing) and rotate the trans for more clearance. Usually nothing else needs to be removed and provides a lot of clearance and view of the guts. I've done that more than once long ago on various manual trans. Of course you'll need to catch all that oil that will pour out.
Problem is only on 1st and reverse. No issues going 2nd to 3rd. In gear it's quiet. It grinds cogs trying to get it into 1st or reverse when the engine is running. I can force it in but it won't be doing the gears any good to say the least. If I stop the engine I can easily get it in gear. Sometimes from stand still with the engine running it will easily go into 1st.
T Nothing in that description seems to indicate it is hanging up, or sticking. But it does describe the indications of a clutch that is not fully releasing. Or, you are not allowing enough time for the gears to slow after depressing the clutch. I'd suggest removing the lower cover from clutch housing, assuming it has one. Have someone depress the clutch, or block it down with the old board between the pedal and seat trick. Measure the clearance between the disk and flywheel then report back. I think most recommend about 60-80thou.
Or the pilot bushing is sticking on the pilot shaft, not allowing it to stop spinning when the clutch pedal is pressed down.
Remembering back to way back when, memory says that those transmissions don't like high idle speeds when trying to go into gear. You did install the disk with the correct side facing the flywheel? That should make some noise when the clutch pedal is pushed in. Speaking of clutch pedal, did you adjust the clutch so you have right at one inch of freeplay?
I will try lowering the idle speed and see if that helps. Clutch disc definitely went in the right way around. I'm sure clutch adjustment is part of it. Will find out on Saturday when I get it up on axle stands.
I adjusted the SynchroLoc again, that was fine. I set the clutch gap on release to 45 thou it was about 15. I also found the side shift levers I had laser cut in stainless were fouling each other so that the rear lever in its full forward position was hitting the front lever - making it difficult to fully engage first. I've relieved that so it has plenty of clearance. I've also taken the advise about leaving it in neutral with the clutch pedal depressed for about ten seconds before going into first. I knew that T85's simply won't shift into first while still moving. Putting all that together it is shifting cleanly into reverse and first. So a successful afternoon (touch wood!!). I need to test that it doesn't now slip when accelerating in top. Hopefully it won't. Was also pleased to see that I don't have the dreaded leaking rope seal on the back of the crank.
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