TH350 Problem

Terry Cain · 10-23-2021, 07:45 PM

60's pretty good first pass off of trailer. second pass will slow about 3 on 60. Third pass will slow even more. Will slow as much as a tenth on 60. Everything has been pulled a part and check by several people. New valve body. New clutches (several times) Only thing that has not been replaced is the case. Can take the convertor and put it on another (spare) trans and it is very consistent on 60's. Any suggestions? Need to add. I can put spare trans in and use same dipstick on both trans so fluid level is the same.

Angelo DiTocco · 10-23-2021, 09:08 PM

do you have a pressure gauge for the trans?

Mark Yacavone · 10-23-2021, 09:49 PM

Do you have a temp gauge on the trans?

Terry Cain · 10-24-2021, 05:52 AM

Quote:

Originally Posted by Angelo DiTocco

do you have a pressure gauge for the trans?

160

Angelo DiTocco · 10-27-2021, 06:32 PM

Quote:

Originally Posted by Terry Cain

160

I assuming the pressure is the same in both trannys?

Terry Cain · 10-28-2021, 05:26 AM

Quote:

Originally Posted by Angelo DiTocco

I assuming the pressure is the same in both trannys?

Hmmmm, good question. Have not put a gage on "spare" trans because of no problems. All books and literature shows 145-170 is good number.

Mark Ugrich · 10-28-2021, 11:10 AM

Is your pressure gauge mounted in the car or is it a diagnostic type for stationary pressure diagnosis?

Henrys Toy · 10-24-2021, 08:56 AM

Quote:

Originally Posted by Terry Cain

60's pretty good first pass off of trailer. second pass will slow about 3 on 60. Third pass will slow even more. Will slow as much as a tenth on 60. Everything has been pulled a part and check by several people. New valve body. New clutches (several times) Only thing that has not been replaced is the case. Can take the convertor and put it on another (spare) trans and it is very consistent on 60's. Any suggestions? Need to add. I can put spare trans in and use same dipstick on both trans so fluid level is the same.

Good Morning Terry,
I had a similar problem a few years back with a GM/Chevrolet PG case.
I had changed over from "sleeve type bushings" to Roller Bearings and followed the recommended clearance tightening and the trans would slow the car down as we started hot lapping the car. I loosened the "end play" about .003 to .005 overall and the problem stopped.
My spare Glide ( also a GM case) was set up with the recommended tighter clearence's and wouldn't slow down as it got hotter.
So is the case growing and tightening up or is it the front pump, maybe its an alum. drum or hub, sorry I don't have a exact answer, but I found running a little more end play clearence did "fix" my problem at the time.

Respectfully,
Henry Kunz 1534 H/SA

Terry Cain · 10-24-2021, 07:13 PM

It does have the aluminum stuff in it and also a new pump.

Mark Yacavone · 10-24-2021, 10:33 PM

I don't know about the 'glide but you don't want to loosen a T 350 up much. Keeping them snug helps them in the direct drum area.
I asked about the temp, because, if the converter is already on the loose side of things, the warmer fluid could hurt it.

10-23-2021, 07:45 PM	#1
Terry Cain Senior Member Join Date: Feb 2008 Location: Georgetown, Indiana (close to Louisville, KY) Posts: 760 Likes: 492 Liked 224 Times in 103 Posts	TH350 Problem 60's pretty good first pass off of trailer. second pass will slow about 3 on 60. Third pass will slow even more. Will slow as much as a tenth on 60. Everything has been pulled a part and check by several people. New valve body. New clutches (several times) Only thing that has not been replaced is the case. Can take the convertor and put it on another (spare) trans and it is very consistent on 60's. Any suggestions? Need to add. I can put spare trans in and use same dipstick on both trans so fluid level is the same. __________________ Terry Cain ???? STK tcain@twc.com Last edited by Terry Cain; 10-23-2021 at 08:26 PM.

10-23-2021, 09:08 PM	#2
Angelo DiTocco Senior Member Join Date: Dec 2001 Location: NY, NY Posts: 735 Likes: 156 Liked 172 Times in 38 Posts	Re: TH350 Problem do you have a pressure gauge for the trans? __________________ Angelo DiTocco '98 Firebird SS/HA '98 Firebird B/SA

10-23-2021, 09:49 PM	#3
Mark Yacavone Veteran Member Join Date: Mar 2002 Location: Miles From Nowhere Posts: 7,419 Likes: 2,583 Liked 4,453 Times in 1,694 Posts	Re: TH350 Problem Do you have a temp gauge on the trans? __________________ We are lucky we don't get as much Government as we pay for..... Will Rogers

10-28-2021, 11:10 AM	#7
Mark Ugrich Member Join Date: May 2011 Location: Auburndale,Florida Posts: 201 Likes: 20 Liked 57 Times in 32 Posts	Re: TH350 Problem Is your pressure gauge mounted in the car or is it a diagnostic type for stationary pressure diagnosis?

10-24-2021, 07:13 PM	#9
Terry Cain Senior Member Join Date: Feb 2008 Location: Georgetown, Indiana (close to Louisville, KY) Posts: 760 Likes: 492 Liked 224 Times in 103 Posts	Re: TH350 Problem It does have the aluminum stuff in it and also a new pump. __________________ Terry Cain ???? STK tcain@twc.com

10-24-2021, 10:33 PM	#10
Mark Yacavone Veteran Member Join Date: Mar 2002 Location: Miles From Nowhere Posts: 7,419 Likes: 2,583 Liked 4,453 Times in 1,694 Posts	Re: TH350 Problem I don't know about the 'glide but you don't want to loosen a T 350 up much. Keeping them snug helps them in the direct drum area. I asked about the temp, because, if the converter is already on the loose side of things, the warmer fluid could hurt it. __________________ We are lucky we don't get as much Government as we pay for..... Will Rogers