"Rebuilt" A4LD 1st gear slips, 40-45 mph shudder

[arco777]

94 A4LD. Supposedly rebuilt with new torque converter.

First gear feels like it is slipping, more so when trans is hot. Like you're pulling a trailer or something.

Also from about 40-45mph there is a shudder and the truck doesn't feel like it wants to accelerate unless you apply significantly more throttle; above that speed it's fine.

Done so far: New trans fluid. Bands adjusted. No codes thrown. TC stall speed checked OK, TC is locking/unlocking properly.

Trans pressure tester is in the mail. I'm willling to throw parts at it with recommendations (new servos, boost valve, shift kit maybe???).

Any help is greatly appreciated!

 

[wood1]

Slipping you say? The sensation of pulling a trailer and a slipping trans don't quite jive for me. If it was slipping and you press harder on the gas you should get a raise in engine rpm without an increase in vehicle speed.

You have the ATSG manuals for the A4?

If I was going to mess with the VB I would (and did) rebuild it completely using Glacier's thread.

 

[arco777]

Thanks for the reply Wood1. I don't have any manuals except the Ford TSP for the Explorer, which is useful and should be enough for a rebuild I think. I'll look into the valve body rebuild if I can get the free time.

As for slipping vs towing sensation... It's like trying to take off in second gear. Which I suppose it could be doing...

 

[wood1]

Have you tried selecting 1st rather than drive and starting off to see if you are starting in 2nd?

PM me your email address and I will send you the PDF of the ATSG manual. Very informative.

 

[wood1]

Meant to ask you too if that shudder happens when the engine is cold or once it is up to operating temps. The converter does not lock until the engine is warm, helps it warm up quicker. Could be the converter shuddering when it locks.

 

[arco777]

I haven't been driving that Explorer lately; but if I recall correctly, manually putting it in first didn't make a difference.

The shudder seems to be whether cold or warm. Anytime I manually unlock (tap brakes) the torque converter or notice it lock up, it does it smoothly.