1990 Cherokee automatic-no reverse

[Speed]

Hi Moses;

   Dutch just bought a '90 Cherokee,4.0 straight six and automatic. Everything looks to be in very good shape and works fine except it has no Reverse. I'm told the forward gears all work fine. My first instinct is to drop the pan,look for debris and do a filter/fluid change,but if there's something else more likely to be wrong,I can pass it on for him to check. He's building this for his grandson Wade and his wife and kids to use. They're using Wade's old Chevy 4 wheel drive truck for transportation,but living in Washoe Valley it's killing 'em in gas,and it's a tight fit taking the family anywhere. I'll try to get 'em both logged on here later.

   Speed

[Moses Ludel]

Speed...1990 is the last year for the Renix 4.0L EFI/MPI, in 1991 the Mopar MPI came on board with a cylinder head change as well.  The Wrangler gained the 4.0L Mopar MPI engine, too.

 

The transmission is an AW4, overall a very reliable unit that often givens 200K plus miles of trouble-free service.  While a fluid and filter change has been known to "cure" some transmission woes, I'd be looking at the shift linkage adjustment, line pressure testing, a bad direct clutch, a worn first/reverse brake or a worn or damaged overdrive clutch.  Would not hurt to adjust the shift linkage carefully and change the fluid and filter.  Beyond these modest undertakings, the next level troubleshooting is on the bench looking at hard parts damage within the transmission.  A used unit might actually offer service in these models.  There are many automatic transmissions that do not have the capacity for "good used" status.

 

My how-to videos at Vimeo On Demand are popular, and the AW4 is in my sights.  When our XJ Cherokee's unit needs a rebuild, it will likely end up a step-by-step streaming rental star...There are many AW4 units due for a thorough rebuilding! 

 

Moses

[Speed]

I think you're right-a used trans. might be a good way to go. I think I'd go ahead and service it before installation,and maybe give it a can of that Lucas Trans. saver or Trans-X treatment. I told Dutch he'd be well advised to install a separate Trans. cooler too,just for safety sake. Personally,I'd bypass the cooler in the radiator,but I guess that's something a person has to decide for himself.

   Today I scored a BRAND NEW motor for my compressor!   I have a friend who's an Industrial Electrician,so I'll have him double check my wiring to be sure it won't smoke THIS motor. I THINK the last "free" motor just had a dry bearing that failed,but I didn't have the wiring looked at,so I don't know that for sure-it ran well for about 4 hours before it slowed down and started to smoke. Another few days I can install it and see if I have BIG air.

   Speed

[Moses Ludel]

Yea for big air!  See my compressor account at the magazine, you'll get a kick out of it:  http://www.4wdmechanix.com/Downsizing-and-Air-Compressors!.html.

 

Moses

[Speed]

Good article,Moses. I had to laugh at your description of people's "It worked great last time I used it,just before the big flood of '92-but it was only under water for a week..." kinda commentary on the units they're trying to sell. Dutch gave me this compressor,with a 3 hp motor he tried to use to replace the original that melted down. I traded a bunch of bamboo flooring for another motor,which lived for a couple of hours of operation before it melted down.

   Speed