1985-1998 [Subscribe to Daily Digest] |
![]() | [Main 9000 Bulletin Board | BBFAQ |
Prev by Date | Next by Date | Post Followup ]
Member Login / Signup - Members see fewer ads. - Latest Member Gallery Photos
Re: Another bad tranny question Posted by CMyles [Email] ![]() ![]() In Reply to: Another bad tranny question, Kirk Coles, Wed, 7 Dec 2005 19:09:34 Members do not see ads below this line. - Help Keep This Site Online - Signup |
Kirk, I rebuilt a bunch of these ZF4HP-18's and if I engage my memory I may be able to help you a little. I actually like these tranny's and the later units were generally OK. The valve body is on top which is cool because you can remove it and do air pressure tests on the stack without even getting dirty. Needless to say when you have a lack of drive problem it can be the torque transmitting "stack" or the fluid control system which engages the various clutches of the stack. That part consists of the valve body and govenor. You can also have an input problem or a torque convertor problem and then, because this is a transaxle there is the final drive (differential). The fact that you have reverse narrows the search considerably. What happens if you shift into "1" and give it the gas? Now, what is preventing forward drive is that the forward clutch is not engaging or the low roller clutch is shot. How does the ATF smell and look? Is it burned and black/dark (should be crimson colored Dexron III). Is it low on ATF? It's a small matter to remove the valve body and do those air pressure tests of the clutches and that's how you'll know if the forward and roller clutch are OK. The quick dirty check of the valve body is to toss in a known good one and see what you get. This is a big complex V.B. and several different valve problems can cause your symptoms. Sometimes the V.B. can be cleaned, rebuilt and made OK and sometimes not. Repost if you need more info.
posted by 206.123.221...
No Site Registration is Required to Post - Site Membership is optional (Member Features List), but helps to keep the site online
for all Saabers. If the site helps you, please consider helping the site by becoming a member.
![]() |
![]() |
![]() |
![]() |
![]() |