88 250 4x4 7.3 it seems that the motor is making the trans mount move enough that at higher rpm in 4 and 5th gear the clutch slips. move it back and the problem goes away until it moves it again. bolts are tight and i checked trans mount and motor mounts seem ok. whats up? it never did this before and clutch is about 5,000 miles new. and is dry not oil soaked. is this common with high torque motor. thanks

 

Have you checked the firewall by the booster, there was a Tech bullitin re cracking of the area around the booster which causes problems with clutches.

 

The trans and engine could be missaligned, Have you checked the bolts that mount to the engine?

 

they were tight, thats what i thought. i don't understand why it moves the trans. mount in the bolt holes, this must take alot of torque. maybe i will check motor mounts again.

 

With a hydraulic clutch it should not make any difference if the transmission moves back and forth as far as the clutch goes.

I have a friend that does transmission work for a living.

He has to swap transmission cases on several ZF 5 trannies every year because the case cracks on them due to the high torque of the diesel engine.
Inspect your case very carefully for cracks around what would be where the bell housing attaches to the transmission on a two piece unit. Flex in that area would cause the clutch to engage under torque.

I haul and tow heavy, he talked me out of installing a ZF 5 because it would not stand up to what I use my truck for.
Not to many people will do that when it results in a lost sale for them.

 

thanks dave, i have a friend that turned wrenches for years, he also said he had replaced many cracked ones. what do you have the 4 speed? i guess the zf 5 trans. are hard to come by?

 

I can find lots of them here...for a price.
Well 1500 installed is not to bad, I would probably save that in a year of driving.

I have a T 19 but sure would like OD with the current fuel prices, I am expecting close to 4 dollar a gallon fuel by Janurary this year, I am in WV where a lot of people use heating oil.

I had a ZF 6 and transfer case lined up to install till I found out I would have no speedo.The trucks that it was installed in had the rear axle sending unit.

The only thing left to do is a Gear Vendors OD unit I guess.
Right now my truck is down with a cracked block so I may wind up getting a different truck, I have had about all I can stand of reman motors. Three failures in 18 months is to much.

 

OUCH, that has to hurt.

 

Well legal action is going to be the next step.


Want a good reman engine....let me recommend www.reviva.com

I have walked for 3 months out of that 18 months with engine failures. That is more than the truck has been down with the original motor since 1986.

 

be a good arguement point for rebuilding what you have rather than buying a reman, costs more, but with a reputable local builder, likely to hold out better... it would appear I got lucky on that, mine was rebuilt before I bought the truck, but it never was repainted like the remans like to do, so I believe it to be a local builder. So far it has been a real good engine and truck for me.

 

The time was the determiming factor for me.
Reman and the truck was down for one day.
Rebuild what I had, the local shop was quoting 6 weeks downtime.

As it turned out though, the reman has been down for 12 weeks since it was installed, and right now we are at a deadlock in resolving the problem so I see no end to the walking.