I've got an 85 4spd muncie. The tranny has about 136,000 on it with a lot of recent hardshifting. My reverse grinds most of the time and a few months ago i noticed when i got into 3rd during hard acceleration and/or if i shift into 3rd over 3500. Are the synchro's in 3rd and Reverse screwing up. I wanted to rebuild it but what should i get? Any help would be awesome. Thanks everyone.

There are no syncros in reverse. Either you are shifting with the car moving, the engine is spinning too fast when you go into reverse (IE blipping the throttle), or your clutch isnt fully disengaging. Im betting the last, you probably just need to bleed the air out of the clutch system. Its not complicated, but it takes a while to explain, and its been covered literally hundreds of times on here, so im going to have to tell you to search for it.

hmmm-i just put in a new ram clutch, mater and slave cylinder about a month or 2 ago. i know the lines are free of air. i dont have my foot on the gas, my idle is at about 1000 and i've got the pedal down to the floor. What else would cause it to grind in reverse, its been doing it since i got the car 2 years ago and my uncle said it was doing it for a large part of the 6 years he owned it. What would cause the grinding in 3rd?

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Black/ Silver 85' GT
Rebilt 87' engine
Bored .030 over block ~9.5-9.7 Compression
Probe Forged Pistons 440 Cam
ARP Rod Bolts Per. Valve Springs
Roller Timing Chain Blaster Coil
Flowmaster 80 Series CRX Intake
Bosch Plugs+ Wires 8" Subwoofer

yes, as mentioned - reverse has no synchro
new cyl's does not mean they are good
but, I'd be more looking at poorly adjusted shift cables. it usually takes me a few minor tweaks on the cables after a fresh install - and you did have to undo them to change the clutch.

bleed cyl's & adjust the cables. since its reverse & 3rd - the "up" positions on the shifter - I'd say move the shifter cable at least an 1/8" towards the front on the car (on the shift lever)

also - there is the bent clutch pedal. this is a common problem, and keeps the clutch from fully engaging.

The bent clutch pedal is an awefully good bet if your system is bled properly and your cables engaging fully. When the car is in reverse, you can check on the transmission casing to see if the lever is fully engaged. It should normally be on the Muncie.

Another help is to put Synchromesh in the tranny. I tried other lubricants and had sticking problems until I put in Synchromesh fluid.

Mine still grinds sometimes in going into reverse if the tranny is still revving when I go from neutral. Sometimes clearing into first before going into reverse helps this.

Hope this helps.

Arn

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There is no other option than the clutch not fully disengaging. For some reason the input shaft is spinning faster than it should, either the clutch is dragging, the gears are moving relative to the shaft (car moving) or the engine is revving.

It could be a pedal. You can look under the dash, there is a stand off that the master cyl attatches to, its U shaped, it should be square with the pedal. That or there is air in the system. As for grinding into 3rd, that could be a weak syncro, but a dragging clutch certainly wouldnt help, Id see what happens once the reverse is fixed.

Syncromesh might help some, but you shouldnt need it not to grind going into reverse.

well i put in some lucas treatment to see if that would help. Is there something better i should be putting. I was wondering about that pedal. It must have been pushed down over a million times since 1985 so i wouldn't expect steel to stay new after that kind of abuse. Ill get a new pedal and adjust the cables. As far as 3rd, it would mostly grind when i would race or if i would shift over 3000 after i've been driving around all day. I had a small race on saturday and it grinded going into 2nd for the first time. I'm pretty sure its a combo of the cables and pedal. It started grinding into 3rd before my engine swap last year but i'll check it out. Thanks for all the help guys.

The steel pedals are fine, its the aluminum ones that bend.

I dont really see how any amount of misadjustments in the cables would cause it to grind. Maybe if it was just too short to fully engage the gear, but then you wouldnt be able to get it to lock into gear. The cables just actuate the levers on the tranny, its not like them being misadjusted is going to effect how the gears are engaged, it would just make it hard to reach gears.

As for the lucas, I dont know if that would hurt or not. Its main purpose is to decrease viscosity breakdown under heat in the engine, the tranny doesnt get that hot, it will increase the viscosity when cold some, I dont know if the gummyness of it would hurt anything in a transmission though.

sorry-i got my metals mixed up. The stock is the aluminum and steel combo and the aftermarket is steel. Is there something better than the lucas i can put in? I remember having to adjust the cables after i put my new clutch in. It was grinding going into 1st at idle so i moved the rigth cable up a little, tightened down the bolt and it was fine. Maybe the left cable needs to be adjusted for 3rd? The only weird thing is it shifts fine when just driving around normally but when under hard acceleration it goes in....it just goes in grinding.

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Black/ Silver 85' GT
Rebilt 87' engine
Bored .030 over block ~9.5-9.7 Compression
Probe Forged Pistons 440 Cam
ARP Rod Bolts Per. Valve Springs
Roller Timing Chain Blaster Coil
Flowmaster 80 Series CRX Intake
Bosch Plugs+ Wires 8" Subwoofer

quote Originally posted by Pyrthian: also - there is the bent clutch pedal. this is a common problem, and keeps the clutch from fully engaging.

Ummm.... you mean disengaging, right?

here is what your clutch pedal should look like, kind hard to tell depth,. but is should sit about an inch higher/ closer to you than the brake pedal

also, since its a 4 speed, do a search in the archives on 4 spped shifter cable adjustment, it helps alot

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WTB: Getreg, tan floormats


AIM:Onefast2M8
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86 GT SC 3800 Intercooled
07 G6 GTP

ummm ok...so...ugh...my clutch pedal is about even with my brake pedal. I think i found a part to the problem. I've been driving it easy lately and its doing pretty well. I feel really stupid for 2 reasons: 1) yes i did mean disengage (i ALWAYS get those mixed up) and 2) As far as reverse i would be moving a little when going into reverse (coming out of a driveway etc.). I think i got the reverse issue fixed and i also found another problem. Don't ask me how, but my rear tranny mount nut came off. The bolt for the mount was stripped from rubbing up against the cradle. I put a new one and it seems to be doing better now. Can anyone 2nd getting a new pedal as a good idea?

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Black/ Silver 85' GT
Rebilt 87' engine
Bored .030 over block ~9.5-9.7 Compression
Probe Forged Pistons 440 Cam
ARP Rod Bolts Per. Valve Springs
Roller Timing Chain Blaster Coil
Flowmaster 80 Series CRX Intake
Bosch Plugs+ Wires 8" Subwoofer

The reverse grinding thing can be resolved by shifting into first before taking reverse each time.

The height of the pedal is not important, you need to see if the standoff is still square with the pedal body.

The transmission will always grind if you are moving foward shifting into reverse.

i would never go into R when going forward, only rolling back a little. The R problem is fixed. I just shift very gently when at a dead stop. Whats the best way to see if the pedal is still square?

my tranny is actually doing really good. i've been taking it easy. I've been trying to double clutch but its hard since the throw is so long. Don't even know if that really helps anything. I've also been shifting kinda slow and pausing in neutral going into 3rd. It hasn't been grinding at all. I still need to reaplace my 1/2 shaft seals. Thats where my tranny leak is coming from. Thanks for the help everyone.