[aaronv54]

I have a 99 Safari AWD with around 115k on it.

After driving it on the interstate for awhile and getting off (after it gets hot I guess?) it "lurches" when it shifts from a stop at around 20mph and again around 40mph. The "lurch" is similar to what happens when shifting from neutral into drive while the engine is racing, but not nearly as severe.

Any ideas as to what it could be? Is a new transmission in my future? We have had this vehicle since it had 18k on it and have not had service/repair done to the transmission before.

 

[Gus_Mahn]

Another old post, but I can answer it. Hopefully it will help someone. Some of these transmissions seem to have issues with the lock-up torque converter spool valve in the valve body hanging up. This generally happens at highway speed usually around hills. When this happens, the computer sees the lock-up torque converter slipping, goes into limp home mode, and applies full line pressure to prevent this slippage. This causes extremely harsh shifts.

There are two possible fixes. 1 some trans guys make a paste out of scouring powder and polish the bore after removing the valve body. This is cheaper than option 2, but I'm not sure of the cost. 2 The other option is to ream out the bore and install a bushing (valve body removed). This repair costs about $400.

 

[astro355]

Wow, you could get an aftermarket valve body for that price.

 

[2002Safari]

Any OBDII codes yet?

I would start by replacing the separator plate. I would expect you have some pitting where the shutoff balls it the plate.

The separator plate is quite easy to replace. You have I believe 7 ball bearings to keep track of. The separator plate and plate gaskets will cost around $30 USD and a days work.

When I did mine I also did a shift correction kit. Were I doing it again, I would just do the separator plate as I don't like the stiff shifts.

Have you done a transmission flush? A flush is 12 quarts and needs two people.