205 problem - The 1947 - Present Chevrolet & GMC Truck Message Board Network

OLDCHEV4X4 · 07-11-2007, 07:51 AM

My 205 TC has a problem. This is in my race Blazer so it gets abused and it stays in 4 low all the time. Its a 205/th350 combo.
When i put it in reverse it wouln't move. When i put it in 1, 2, or 3 it moves. This happened in the middle of a race.
I figured it was the trans. No problem, one of my sponser's is a trans guy and he was there and said it was the reverse oneway clutch.
Ok so i get home, take it out, and give it to him. He calls me and says there is nothing wrong with the trans. He says check the slider and shifter fork in the TC.
So i open up the TC and don't see anything obvious. The upper shifter fork has .025 play between the side of the fork and the groove of the slider. The slider has some slop in it, but i dont think its too much.
Has any one else had this problem???
I wish i had tryed 4 hi before i took it out of the truck!

eedgell · 07-11-2007, 09:10 PM

If the transfer case is engaged, and will go forward, I have never heard of them not working in reverse. I dont think it is mechanically possible.. Is it.? Has to be in the transmission or its linkage.

**kwmech** · 07-11-2007, 09:47 PM

I would be looking at one of the diffs failing before a 205. They are pretty tough, I've seen just about 800HP going thru one without failure.

Thought: you didn't specify why the vehicle didn't move. Did the engine rev like in neutral or did it bind up?

*trkklr77* · 07-11-2007, 10:01 PM

its not the tcase. it either work 100% or it doesnt.

OLDCHEV4X4 · 07-12-2007, 07:52 AM

kwmech, it reved like it was in neutral. I checked trans fluid, looked for leaks. After this happend i drove 10 minutes back to the pits. I had all 3 foreward gears, but still no reverse.
My trans guy is real good. The jeep dealership brings him transmissions to fix because they cant. He's been building HP transmissions for 20 years. So when he says the trans is ok, I believe him.
I have a extra 205 TC that i'm going to throw in and see if that fix's it.

I forgot to mension that once i got back to the pits, it did back up but it was jerking back and forth and making noise. Then it wouldn't move back any more.

b.sharp · 07-13-2007, 07:10 PM

I've had the same problem in an 80's blazer and it was the reverse clutches slipping. All forward gears worked for a few days and then 1st and overdrive went out because they are in the same clutch pac. I believe I would ask him about looking at the clutch disks to see if they're worn or have any appearance of hot spots. That's just my two cents worth. I have never seen a transfer case not work in reverse and work in forword and I grew up with a dad and uncle that did a hole lot of 4 wheelin through you name it they'ld put their trucks through it. Dad had a '79 with 6" lift and 3" body lift with 44 ground hogs and would go about anywhere. He's the one they called when they had a truck stuck in a deep hole of mud or water. Man would I love to have that truck today (except for putting gas in it!!!)

OLDCHEV4X4 · 07-17-2007, 07:15 AM

Update:
The Blazer is back together. It backs-up fine. No noise. This is with the same transfer case and the same transmission.
Looks like I'm racing at Line Mountain this weekend!

**Yukon Jack** · 07-17-2007, 09:36 AM

Pretty odd, hope the race goes well for you!

OLDCHEV4X4 · 07-17-2007, 10:09 AM

Yes Yukon it is odd. Didn't find nothing wrong with the trans. (So he says. Mabey he did but he's too embarased to admit it.) I didn't find nothing wrong with the TC. Put it all back together and hope for the best. If it does break, hopefully i'm not 5 miles out on the track when it does.
Thanks for the "hope". I need all the help i can get!

OLDCHEV4X4 · 07-23-2007, 08:55 AM

Update:
Reverse worked fine all day. And so did the TC. Same everything. Its a mystery. I guess i " Got my mojo working".

07-11-2007, 07:51 AM	#1
OLDCHEV4X4 Registered User Join Date: Apr 2000 Location: Chester County PA, USA Posts: 1,228	205 problem My 205 TC has a problem. This is in my race Blazer so it gets abused and it stays in 4 low all the time. Its a 205/th350 combo. When i put it in reverse it wouln't move. When i put it in 1, 2, or 3 it moves. This happened in the middle of a race. I figured it was the trans. No problem, one of my sponser's is a trans guy and he was there and said it was the reverse oneway clutch. Ok so i get home, take it out, and give it to him. He calls me and says there is nothing wrong with the trans. He says check the slider and shifter fork in the TC. So i open up the TC and don't see anything obvious. The upper shifter fork has .025 play between the side of the fork and the groove of the slider. The slider has some slop in it, but i dont think its too much. Has any one else had this problem??? I wish i had tryed 4 hi before i took it out of the truck! __________________ 72 k/10 short wideside 72 k/5 Blazer 72 K/5 Blazer - obstacle course racer 72 custom/10 8' bed 70 K/5 Blazer 67 C-30 GMC Flat bed 86 GMC K2500 Plow Truck 85 GMC K3500 84 M1008 85 M1008 77 G30 Motor Home 72 Sears 12hp Tractor Glenmoore, Pennsylvania

07-11-2007, 09:10 PM	#2
eedgell It's the air up here Join Date: Mar 2007 Location: Western Colorado Posts: 710	Re: 205 problem If the transfer case is engaged, and will go forward, I have never heard of them not working in reverse. I dont think it is mechanically possible.. Is it.? Has to be in the transmission or its linkage. __________________ 1971 cheyenne k10 4 speed np 205 454 BB factory a/c Never drink down stream of the herd! Eric

07-11-2007, 09:47 PM	#3
kwmech Senior Member Join Date: Mar 2003 Location: Colfax-California Posts: 8,650	Re: 205 problem I would be looking at one of the diffs failing before a 205. They are pretty tough, I've seen just about 800HP going thru one without failure. Thought: you didn't specify why the vehicle didn't move. Did the engine rev like in neutral or did it bind up? Last edited by kwmech; 07-11-2007 at 09:49 PM.

07-11-2007, 10:01 PM	#4
trkklr77 Account Suspended Join Date: Aug 2006 Location: vacaville ca, because it as far from indy as i can be Posts: 775	Re: 205 problem its not the tcase. it either work 100% or it doesnt.

07-12-2007, 07:52 AM	#5
OLDCHEV4X4 Registered User Join Date: Apr 2000 Location: Chester County PA, USA Posts: 1,228	Re: 205 problem kwmech, it reved like it was in neutral. I checked trans fluid, looked for leaks. After this happend i drove 10 minutes back to the pits. I had all 3 foreward gears, but still no reverse. My trans guy is real good. The jeep dealership brings him transmissions to fix because they cant. He's been building HP transmissions for 20 years. So when he says the trans is ok, I believe him. I have a extra 205 TC that i'm going to throw in and see if that fix's it. I forgot to mension that once i got back to the pits, it did back up but it was jerking back and forth and making noise. Then it wouldn't move back any more. __________________ 72 k/10 short wideside 72 k/5 Blazer 72 K/5 Blazer - obstacle course racer 72 custom/10 8' bed 70 K/5 Blazer 67 C-30 GMC Flat bed 86 GMC K2500 Plow Truck 85 GMC K3500 84 M1008 85 M1008 77 G30 Motor Home 72 Sears 12hp Tractor Glenmoore, Pennsylvania Last edited by OLDCHEV4X4; 07-12-2007 at 08:41 AM.

07-13-2007, 07:10 PM	#6
b.sharp Registered User Join Date: May 2006 Location: Frankfort, Kentucky Posts: 508	Re: 205 problem I've had the same problem in an 80's blazer and it was the reverse clutches slipping. All forward gears worked for a few days and then 1st and overdrive went out because they are in the same clutch pac. I believe I would ask him about looking at the clutch disks to see if they're worn or have any appearance of hot spots. That's just my two cents worth. I have never seen a transfer case not work in reverse and work in forword and I grew up with a dad and uncle that did a hole lot of 4 wheelin through you name it they'ld put their trucks through it. Dad had a '79 with 6" lift and 3" body lift with 44 ground hogs and would go about anywhere. He's the one they called when they had a truck stuck in a deep hole of mud or water. Man would I love to have that truck today (except for putting gas in it!!!) Last edited by b.sharp; 07-13-2007 at 07:11 PM.

07-17-2007, 07:15 AM	#7
OLDCHEV4X4 Registered User Join Date: Apr 2000 Location: Chester County PA, USA Posts: 1,228	Re: 205 problem Update: The Blazer is back together. It backs-up fine. No noise. This is with the same transfer case and the same transmission. Looks like I'm racing at Line Mountain this weekend! __________________ 72 k/10 short wideside 72 k/5 Blazer 72 K/5 Blazer - obstacle course racer 72 custom/10 8' bed 70 K/5 Blazer 67 C-30 GMC Flat bed 86 GMC K2500 Plow Truck 85 GMC K3500 84 M1008 85 M1008 77 G30 Motor Home 72 Sears 12hp Tractor Glenmoore, Pennsylvania

07-17-2007, 09:36 AM	#8
Yukon Jack Post Whore Join Date: Feb 2000 Location: Rose Hill, KS, USA Posts: 12,686	Re: 205 problem Pretty odd, hope the race goes well for you! __________________ 1970 Blazer with a 400 sbc and 4" lift 1980 Pontiac Trans Am, 455 Oldsmobile 2012 Kawasaki Concours 14

07-17-2007, 10:09 AM	#9
OLDCHEV4X4 Registered User Join Date: Apr 2000 Location: Chester County PA, USA Posts: 1,228	Re: 205 problem Yes Yukon it is odd. Didn't find nothing wrong with the trans. (So he says. Mabey he did but he's too embarased to admit it.) I didn't find nothing wrong with the TC. Put it all back together and hope for the best. If it does break, hopefully i'm not 5 miles out on the track when it does. Thanks for the "hope". I need all the help i can get! __________________ 72 k/10 short wideside 72 k/5 Blazer 72 K/5 Blazer - obstacle course racer 72 custom/10 8' bed 70 K/5 Blazer 67 C-30 GMC Flat bed 86 GMC K2500 Plow Truck 85 GMC K3500 84 M1008 85 M1008 77 G30 Motor Home 72 Sears 12hp Tractor Glenmoore, Pennsylvania

07-23-2007, 08:55 AM	#10
OLDCHEV4X4 Registered User Join Date: Apr 2000 Location: Chester County PA, USA Posts: 1,228	Re: 205 problem Update: Reverse worked fine all day. And so did the TC. Same everything. Its a mystery. I guess i " Got my mojo working". __________________ 72 k/10 short wideside 72 k/5 Blazer 72 K/5 Blazer - obstacle course racer 72 custom/10 8' bed 70 K/5 Blazer 67 C-30 GMC Flat bed 86 GMC K2500 Plow Truck 85 GMC K3500 84 M1008 85 M1008 77 G30 Motor Home 72 Sears 12hp Tractor Glenmoore, Pennsylvania



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