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Old 10-06-2013, 02:42 PM   #1
Join Date: Sep 2013
Posts: 20
transmission issues!

Hey guys! maybe I can pick your brains for a minute

I have a 1997 jeep wrangler 4.0 5speed that I picked up a couple weeks ago. I LOVE my new baby. Its got a couple issues that I want to address but the most concerning is a pretty bad grind going into reverse. Im aware these trannys dont have synchros for reverse, so ive tried putting it into a forward and then into reverse and it still grinds.... any other thoughts?

Its got 127k miles on it, and im not sure if the tranny fluid has ever been flushed so im nervous to do that, as ive read that if you dont change the tranny fluid every 60k or so, its better to never do it at all. Im not sure the logic behind this, but ive heard it a bit on forums before..

how long do these transmissions last? is it just about time to switch it out?

thanks for your help guys!

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Old 10-06-2013, 04:15 PM   #2
Knows a couple things...

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Join Date: Nov 2005
Location: Escondido, Calif.
Posts: 39,691
The old wive's tales are wrong on it not being good to change the transmission fluid if it has gone too long between changes. Even with an automatic. If a transmission fails after having its lubricant changed, it was about to fail anyway.

Your transmission is an AX-15 and Reverse gear will grind unless you do that momentary shift into a forward gear first before shifting into Reverse. Perhaps your technique isn't quite there yet, I'd keep at it... just the briefest of a momentary shift into any forward gear like 1st before shifting into Reverse (no need to lift up on the clutch) should do it.

Your AX-15 is a little fussy about its gear lube... it requires a GL-4 (not GL-5) 75W-90. A good GL-4 75W-90 is Redline MT-90 which you can get from You can read about MT-90 at

If you don't want to wait to order it, the manufacturer added synthetic 10W-30 engine oil to the AX-15's list of approved lubricants since GL-4 75W-90 can be hard to find on the local store shelves. No worries on the seemingly wide disparity between the synthetic 10W-30 and GL-4 75W-90 gear lube viscosities. They are actually very similar viscosities, engine oils and gear lubes are measured on two different viscosity scales.

When you have a choice, buy American.

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Old 10-06-2013, 06:00 PM   #3
Join Date: Sep 2013
Posts: 20
thanks for the info!

Perhaps your right that its more my technique than the transmission itself because it only grind SOME times. other times it goes right into gear, but feels a little spongey.
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Old 10-06-2013, 09:07 PM   #4
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Join Date: Jul 2013
Location: Snohomish County
Posts: 358
Pump the clutch a couple times sounds like it might not be disengaging all the way may be the slave or master. With no syncros if the gears are moving it will grind. Only two things can cause the gears to move the tires are turning or the engine is running and clutch is engauged or dragging.
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