3t40 minor setback

[TurboGTU]

OK apperently the manuals I got (ATSG revised edition and a cheap Chilton GM rebuild manual) state that the Foward clutch pack is suppose to have .040-.060 clearance...but how come it don't state anything for the Direct or Low/reverse? What do your manuals say? I have put steel plates on both packs and the clearance for both is now .020. Is there any ill effect with this. Direct had about .090 clearance (all 5 frictions and steels)and foward had about .10 using the thicker back plate(waved plate didn't fit-4 frictions 4 steels and back plate). I am using the ALto red eagle clutch kit with Kelone steels. The steels seem a bit thicker than stock foward clutch steels but are the same thickness as the direct. I have not assembled the low/reverse yet. Does anyone know where I can get the Raybestos Kavlar Power Band for this trans...If your shop has it or can order it...let me know Please!. No one I know carries it...just the relined bands.

[Quinky]

RE: 3t40 minor setback

IF you have to much clearance you'll get sloppy shiftings or slippage.. If you have to little clearance you could get clunking on the down shift or extra firm shifts.. a general rule of thumb is a about a nickle thinkness of clearance.. If you are having a proble with clearances you should be able to get different thickness steels.. Messure what clearance you need.. messure your steels and figure out how much thicker or thinner you need and talk to a transmission shop and see if they have anything.. used parts for a 125 are a dime a dozen...

[TurboGTU]

RE: 3t40 minor setback

Yea..got that stright. They are now just right. Not a nicle..but about a dimes worth for both. I've now put some washers on the Diff spider gears and it won't run open..its locked..This could be good for drag but when I turn?...I now need to find two thin washers from the trans store just to keep it super tight..not locked. Every thing else is good..ready for complete essimbly. OH wait. THE DAM BAND. OK..since you have your fancy books there..whats the advantage of me using the latter band (94up) vs the 88-90 stock bands I fryed. Seems like this is the only band I can get. Makco stoped selling the Kavlar...I cain't find the Raybestos...and I have no idea where to get the Alto Red band. Like I said...any help here is verrry apreciated...the only thing holding me back.

[patgizz]

RE: 3t40 minor setback

if you have too much clearance it will also possibly blow the seal off the piston when the piston comes out of its bore too far. had that happen once when i forgot to check clearance.

[TurboGTU]

RE: 3t40 minor setback

Well got the later band. Its a BorgWag . Later bands are suppose to be high energy..I dunno. Its in. I finnaly put all the packs and new thrust washers. Wasn't too bad at all. The only set back was that I put the large low/rev snap ring first and as I was putting the apply piston on...I notice the thin low/rev snap ring staring at me...DAMMIT!. Had to swith them around. But thats it. Now I just need to reassemble the valve body and the channel plate and shes going in.

I also took apart a rebuilt (not me) '88 700r4...no 2nd,slipping 3rd, no 4th. Band was wiped clean of its friction, 3-4 pack is fryed like every difective 700/4l60. there was damage between the prag and the reverse gear...prob missing a bushing there. Im really getting into this trans stuff. Whats the point in have alot of power if it don't make it to the ground.

[asylum-motorsports]

Very interesting.
May I ask what FDR you are running in your 3t40, and how you achieved it?
Thank You.
Eric

[TurboGTU]

Just stock APV van gears...3.33 (30 tooth count final drive sun gear). Sprockets are the same count (35/35)...so its 1:1..and then the final drive is 3.33:1.
So about 112.5mph at 6K rpm with my 205/55/16 tires. + or - about 18.75mph every 1K rpm with Tq converter locked (going to hotwire it for manual locking trick..hehe)
So about 131.26 at 7K. I can take it to 500rpm more or 1K more thanks to the tq this engine can produce to push the car.
Great drag racing/auto-x/rally trans. Has closer gear ratios than a 440t4/4t60 (no flame war..but its true)...and weights less.

[TurboGTU]

Oh yea..the specs so far. It has a FD9B tq converter (f=fwd, D=2095rpm stall, 9=red fiber, B=standar starer(spelling). I bought the Sonnax oil pump shaft, Sonnax billet boost valve, updated doual land 3rd accumulator check valve, new tcc selinoid, Trans Go shift kit, Shimed Diff for limited slip effect, reused old 1-2 accumulator piston and pin..just put a SBC valve spring dampening spring in there to keep it from moving too much in conjuction with OE spring and a washer on the case to save it from scoring it(coun't find Sonnax 1-2 updated piston/pin). Late model high energy band, Alto Red Eagle clutches and Kelone steels. Rebuilt all appy pistons..new seals everyhwere, wired for TCC overide...computer controlled or on (locked) all the time.
I was debating on installing the 2375rpm tq converter (FZ*B) that was on the last fried trans..but I said no because it could be contaminated. I also had the option of installing the 2.84 FD from the fryed trans. But what the heck...im not going to brake no land speed records, and theres no autoban here..My 750il is my daily driver...might as well be quick.

Heres some pics of the build up..
Valve body prep for rebuild..also did pump side.

Rebuilding apply pistons.

Sonnax pump shaft..work of art I must say over the OE junk.

The red frictions..cain't get a good pic after they were in fluid for 1hr...dam glare.. .
Just a paint job. It's official...im calling it..RED...makes sense.

[asylum-motorsports]

Thank you. You have been very helpful.

Do you have a part number for the Trans Go kit? I can't seem to find a source.

Thanx again

Eric

[TurboGTU]

I belive summit sells them...but your in Canada. I got mine from the local trans parts shop. The Trans GO kit covers most 3t40s. Superio also has a shift kit for the 3t40..verry similar results. Superio kits are usualy found on ebay.
Thise are not "high performance" kits. But the might as well be. They quicken up the shifts...less shift overlap...less heat on band and clutches.
SKŪ 125

THM 125
1980 up
Corrects/prevents/Reduces:
3-2 clunk; lockup shudder; reverse slip; converter drain back delay;
late shifts; soft 1-2; band failure.

[asylum-motorsports]

Thank you. I'll check it out

Eric