2.5L to Auto Tranny - Pirate4x4.Com : 4x4 and Off-Road Forum

ROBBY · 03-26-2012, 06:11 PM

Has anybody adapted 4.0L auto or GM auto to a 4cyl jeep motor? I hate the manual for crawling. I haven't been able to find any info on such a swap.

I have a 99 TJ with 60/14b, 5.13's in it, 38.5 SX's, D300 with 4:1's in it. I done it all myself and I am not opposed to having to regear again to run the auto as I can set-up my own gears. I have a rear 60 I can swap in to replace the 14b.

Any one done it or have any info on what needs to be done to do it?

Marty, SoCal · 03-26-2012, 06:45 PM

Some early '90s 2.5l XJ's came with the AW-4 as the auto transmission, 2wd and 4wd. The bellhousing from one of these will fit an AW-4 from a 4.0l. The TCM is different, too, gave a couple hundred RPMs higher shift point spread.

frostytj · 03-27-2012, 04:14 AM

Why not look at the 30RH? It came factory for your year and engine and would bolt right up. Its a 3 speed though if that matters.

Greg Ducato · 03-27-2012, 05:34 AM

Quote:

Originally Posted by frostytj

Why not look at the 30RH? It came factory for your year and engine and would bolt right up. Its a 3 speed though if that matters.

Agreed, your gear and tire combo would run at around 2900rpm at 65mph, I don't think a 2.5 could pull less rpm at that speed. The 32RH has a locking converter and a 2.74 first gear ratio, it is a good little trans and is much shorter overall than any Chevy you might adapt.

ROBBY · 03-27-2012, 06:55 PM

Quote:

Originally Posted by Greg Ducato

Agreed, your gear and tire combo would run at around 2900rpm at 65mph, I don't think a 2.5 could pull less rpm at that speed. The 32RH has a locking converter and a 2.74 first gear ratio, it is a good little trans and is much shorter overall than any Chevy you might adapt.

I don't think I'll be hitting 65 anytime soon...LOL. I don't drive on the highway much at all. Most of our wheeling spots are within city limits so 40-50mph is all I will see. I am just sick of riding the clutch when crawling.

What else would I need? Would I need to change out the ECU to accomodate the auto? Tranny's are like voodoo to me

oldjeep · 03-28-2012, 04:21 AM

Trans, trans cooler, shifter, ecu - might need to change the input shaft on your tcase. Driveshaft lengths will change.

03-26-2012, 06:11 PM	#1 (permalink)
ROBBY Avalon Crawler Join Date: Nov 2002 Member # 15221 Location: NF, Canada Posts: 77	2.5L to Auto Tranny Has anybody adapted 4.0L auto or GM auto to a 4cyl jeep motor? I hate the manual for crawling. I haven't been able to find any info on such a swap. I have a 99 TJ with 60/14b, 5.13's in it, 38.5 SX's, D300 with 4:1's in it. I done it all myself and I am not opposed to having to regear again to run the auto as I can set-up my own gears. I have a rear 60 I can swap in to replace the 14b. Any one done it or have any info on what needs to be done to do it? __________________ TJ on Tons...

03-28-2012, 04:21 AM	#6 (permalink)
oldjeep Pirate4x4 Addict! Join Date: Mar 2001 Member # 3511 Location: MN Posts: 5,387	Trans, trans cooler, shifter, ecu - might need to change the input shaft on your tcase. Driveshaft lengths will change. __________________ Chuck P The clowns'? Oh, yeah, the clowns. We fight them too — entire armies, spilling out of Volkswagons. We do our best to fight them off, but they keep sending 'em in! www.oldjeep.com

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03-26-2012, 06:45 PM	#2 (permalink)
Marty, SoCal Registered User Join Date: May 2011 Member # 191442 Location: SoCal Posts: 261	Some early '90s 2.5l XJ's came with the AW-4 as the auto transmission, 2wd and 4wd. The bellhousing from one of these will fit an AW-4 from a 4.0l. The TCM is different, too, gave a couple hundred RPMs higher shift point spread.